This cake is a chocolate lovers dream - it has dark chocolate cake layers, milk chocolate ganache, chocolate mousse, and a chocolate mascarpone frosting topped with mini chocolate chips. The cake is moist, super chocolatey, and every bite melts in your mouth.
Ultimate chocolate cake
When I created this recipe, I wanted a recipe that literally slaps you in the face with chocolate. All components must be chocolatey. Every bite must be decadent. The cake has the following components:
- Dark chocolate cake layers. Each cake layer is super moist and fluffy, and every bite melts in your mouth. It has an intense chocolate flavor from the dutch processed cocoa powder and strongly brewed coffee, and has chopped dark chocolate throughout the batter.
- Chocolate mousse. The chocolate mousse is by far my favorite part of this cake. It is creamy and smooth and it comes together much quicker than you think. This homemade chocolate mousse is one of my favorite recipes on the blog, so of course I had to put it in this cake.
- Milk chocolate ganache. Now that I have had milk chocolate ganache (I usually use semi-sweet or dark), I am never going back. It is so sweet and creamy, which is why we add a bit of it in between each cake layer (in addition to the mousse) and on top of the cake.
- Chocolate mascarpone frosting. I LOVE this frosting. We use dutch processed cocoa powder for an intense chocolate flavor, while the mascarpone adds a great tang. Think of it like a cream cheese frosting, but milder.
- All purpose flour: all purpose flour is the flour of choice for this recipe. It yields the perfect soft and tender crumb for the cake.
- Dark cocoa powder: dark (aka dutch processed) cocoa powder is the preferred choice of cocoa powder in this recipe. It has a much richer chocolate flavor than regular unsweetened cocoa powder. We also use it in the frosting.
- Leavener: baking powder is used in the cake to help it rise.
- Butter: we use unsalted butter in this recipe to control exactly how much salt goes in. We use unsalted butter in both the cake batter and the mascarpone frosting.
- Fats: the other key fats in this recipe are the vegetable oil, eggs, milk, and sour cream. All of these ingredients add moisture to the cake.
- Sugar: granulated sugar is used to add sweetness in the cakes and the chocolate mousse. We also use powdered sugar in the frosting.
- Coffee: strongly brewed coffee is added to the cake batter - the coffee really deepens the chocolate flavor.
- Heavy cream: a key ingredient in the ganache and the chocolate mousse.
- Mascarpone: mascarpone cheese is a soft Italian cheese that is similar to cream cheese in taste and texture, although I find it to be a bit milder than regular cream cheese. It makes for the perfect frosting!
- Chocolate: the star ingredient! We use all types of chocolate in this recipe. I tested this recipe using Valrhona's baking chocolate, because good quality chocolate is key here. We use dark chocolate (Komuntu 80% Cacao Dark Baking Chocolate) in the cake layers, bittersweet chocolate (Oriado 60% Cacao Bittersweet Baking Chocolate) in the mousse, and milk chocolate (Andoa 39% Cacao Milk Baking Chocolate) in the ganache.
Steps for chocolate mousse
- Pasteurize the eggs. Whisk together the egg yolks, sugar, and salt in a heat proof bowl. Place the bowl over a sauce pan with 2 inches of simmering water and heat for about 5 minutes until the mixture is about 160F. Add the warmed heavy cream and whisk to combine. Remove from the heat and mix in the vanilla.
- Melt the chocolate. Finely chop the chocolate and microwave it in 30 second increments until completely melted. Add the melted chocolate to the egg mixture and mix until combined.
- Whip the heavy cream. Whip your heavy cream for 3-4 minutes until soft peaks form. Add the chocolate/egg mixture to the whipped cream and fold until combined.
- Leave to set. Pour the mixture into a bowl and place it in the fridge to set.
How to make the cake layers
- Whisk the dry ingredients. Whisk together the flour, cocoa powder, baking powder, and salt.
- Beat the wet ingredients. Beat together the butter and oil until combined. Add the granulated sugar and beat until combined. Add the eggs and mix. Add the vanilla extract and mix.
- Combine. Add half of the dry ingredients to the wet ingredients. Then add half of the milk, half of the coffee, and half of the sour cream and mix until just incorporated. Repeat with the other halves of the dry ingredients, milk, coffee, and sour cream. Add the chopped dark chocolate and fold to combine.
- Bake. Separate the cake batter into three 8 inch cake pans and bake for about 30 minutes.
My cake is dry.
Dry cakes are most likely from over measuring the flour. The best way to measure flour is with a kitchen scale - if you don't have a kitchen scale, spoon the flour into a measuring cup then level it off with a knife. Over baking can also result in a dry cake. It is finished when a toothpick inserted into the center comes out clean or with a few moist crumbs.
My cake sank.
Either the batter was over-mixed or the cake was underbaked. It is also possible that your oven has poor air circulation and the cakes needed to be rotated, or the door was open/closed too fast and all the hot air was pushed out of the oven.
My chocolate mousse didn't set.
It is likely that the mousse mixture was over-whipped - over-whipping causes the air in the heavy cream that was originally whipped in to deflate. OR the heavy cream wasn't whipped to medium peaks and therefore there was not enough body.
My chocolate ganache is grainy/my ganache didn't set.
Grainy chocolate ganache could be due to poor quality chocolate, or using chocolate chips instead of baking chocolate. A ganache that did not set is likely from over-measuring the liquid. This is a milk chocolate ganache, and milk chocolate is softer than semi-sweet or dark, so it requires less cream.
For any other troubleshooting questions, feel free to leave me a comment below or message me on Instagram!
Cake baking tips
- Use a kitchen scale. I cannot stress this enough - a kitchen scale is the only way to ensure accurate results. They are cheap and will make cleaning up SO much easier.
- Properly prepare your pans. Line your pan with parchment paper rounds and if necessary, lightly grease the sides so the cake easily releases from the pan.
- Use an oven thermometer. Making sure your oven is calibrated correctly and is at the right temperature is incredibly important for cakes. This recipe was written for the cakes to bake at 325F - any higher and the cakes can over-bake or rise then sink, any lower and the cakes will come out underbaked.
- Use good quality chocolate. I know baking chocolate can be expensive sometimes, but it is so worth it. Poor quality chocolate can ruin the mousse and ganache, so make sure to splurge on the good stuff.
- Refrigerate the cake layers prior to assembling. Cake layers that are chilled are easier to assemble as they are much firmer. If they have any heat to them, the filling/frosting will melt and the cake layers will slip and slide all over the place.
- Make a crumb coat. A crumb coat is a very thin first layer of icing that essentially "glues" the crumbs down and seals in the cakes moisture. After the crumb coat is applied, place the cake in the fridge for 30ish minutes, then finish frosting the cake with the remaining icing.
- Use piping bags. Piping bags are SO useful for cake decorating, especially when there are a lot of components. I put the frosting, ganache, and chocolate mousse in their own piping bags, which I then use to fill/frost the cake.
Prep and storage
- Can I make the cake layers ahead of time? Yes! Once cool, wrap them tightly in plastic wrap. You can freeze them for up to three months. Thaw the cake layers at room temperature.
- Can I make the frosting ahead of time? Yes! You can also make the mascarpone frosting ahead of time. Place the frosting on a piece of plastic wrap and tightly close it. Place it in a ziplock bag and into the freezer. Let it thaw in the fridge.
- Can I make the chocolate mousse ahead of time? Yes, but only a day or two before assembly. Store it in an airtight container in the fridge until ready to use. I would not freeze it and thaw it and use it for the cake.
- Can I make the ganache ahead of time? I do not suggest making the ganache ahead of time.
- Store the baked cake in an airtight container. Any cake exposed to air will become dry pretty quickly, so make sure to secure it properly. Cut the cake into slices and wrap each individual slice with plastic wrap then store in an airtight container in the fridge.
- Freezing the whole cake. If you wish to freeze the entire cake, refrigerate the cake until firm then wrap it completely in plastic wrap so it is fully covered. Then wrap it in tin foil and freeze. Thaw at room temperature for a few hours before serving with the wrapping removed.
- Freezing cut cake layers. If you want to freeze the cut cake layers, wrap them in plastic wrap and store them in an airtight container in the freezer. Thaw at room temperature.
Baking in grams
While I provide volume measurements for the recipes on my blog, I highly suggest baking these recipes using weight. It is the most standardized and accurate way to bake. I carefully recipe test all of my recipes using a kitchen scale, not by using cups, and therefore I cannot guarantee the success of my recipes when using volume measurements.
Other recipes you may like
- Black Forest Cupcakes
- Mini Chocolate Cake
- Double Chocolate Sheet Cake
- S'mores Chocolate Mousse Ice Box Cake
- Chocolate Mousse Pie
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The Ultimate Chocolate Cake
Chocolate Mousse Filling
- 4 egg yolks
- ¼ cup (50 grams) granulated sugar
- ¼ teaspoon salt
- 2 cups (480 grams) heavy whipping cream divided
- ¾ teaspoon vanilla extract
- 8 oz (226 grams) Valrhona Organic Oriado 60% Cacao Bittersweet Baking Chocolate finely chopped
Dark Chocolate Cake
- 2 ½ cups (313 grams) all purpose flour spooned and leveled
- 1 cup (80 grams) Valrhona Dutch Processed Cocoa Powder
- 2 teaspoons baking powder
- ½ teaspoon salt
- ½ cup (113 grams) unsalted butter room temperature
- ½ cup (100 grams) vegetable oil
- 2 cups (400 grams) granulated sugar
- 4 eggs room temperature
- 1 tablespoon vanilla extract
- ½ cup (120 grams) whole milk room temperature
- ½ cup (120 grams) strongly brewed coffee room temperature
- ¼ cup (60 grams) sour cream room temperature
- 1 cup (140 grams) Valrhona Komuntu 80% Cacao Dark Baking Chocolate finely chopped
Whipped Milk Chocolate Ganache
- ⅔ cup (160 grams) heavy whipping cream
- 8 oz (226 grams) Valrhona Organic Andoa 39% Cacao Milk Baking Chocolate finely chopped
Chocolate Mascarpone Frosting
- 8 oz (226 grams) mascarpone cheese room temperature
- 1 cup (226 grams) unsalted butter room temperature
- 2 teaspoons vanilla extract
- ¼ cup (20 grams) Valrhona Dutch Processed Cocoa Powder
- 6-7 cups (720-840 grams) powdered sugar
- 1 pinch of salt
- 1-2 tablespoons whole milk or heavy cream
- mini chocolate chips or chocolate sprinkles, for decorating
- Please read through the entire recipe first, as there are a lot of steps.
Chocolate Mousse Filling
- Before you prepare the mousse, pull all of the ingredients out for the cake layers that need to be room temperature (butter, eggs, coffee, milk, and sour cream).
- Pour 2 cups (480 grams) of heavy whipping cream into a measuring cup. Pour ¾ cup (180 grams) of that 2 cups into a separate cup/bowl, and put the 1 ¼ cups (300 grams) of heavy cream back into the fridge. You will use this later.
- Chop your chocolate and set aside.
- Fill a sauce pan with two inches of water and bring to a simmer over medium heat.
- In a medium-sized heat proof bowl, whisk together the egg yolks, granulated sugar, and salt until smooth. Place the bowl on the pot over the simmering water and continuously whisk while the mixture heats up. It should get to about 160F, although you don’t actually need to use a thermometer if you don’t have one. This should take about 4 minutes on medium heat.
- Meanwhile, microwave the ¾ cup (180 grams) of heavy cream that you set aside for 30-45 seconds. It should be luke warm. Once the egg mixture has reached 160F or it has been 4-5 minutes, slowly pour the warmed heavy cream into the eggs while continuously whisking. Keep whisking the mixture for another 2 minutes. Remove the bowl from on top of the saucepan, add the vanilla extract, and stir to combine.
- Add the chopped chocolate to a microwave safe bowl and microwave it in 30 second increments, stirring in between each increment until completely melted and smooth. You can also do this over the stove using a double boiler.
- Add the melted chocolate to the egg mixture and whisk until completely combined. Set aside.
- Remove the 1 ¼ cups (300 grams) of heavy cream you put in the fridge and pour it into the bowl of a stand mixer fitted with the whisk attachment or a large bowl if using a handheld mixer. Beat the heavy cream on medium-high speed for 3-4 minutes until medium peaks form. Medium peaks are in between soft peaks and stiff peaks - so not fully formed into whipped cream yet, but not super soft either.
- Pour the chocolate/egg mixture into the whipped cream and fold them together using a rubber spatula until combined. Avoid over mixing, as the whipped cream can lose all the air you just whipped into it and deflate.
- Pour the mixture into a large bowl and place in the fridge for 2-3 hours or so until set.
Dark Chocolate Cake
- While the mousse is setting, make the chocolate cake. Preheat oven to 325F and line three 8 inch cake pans with parchment paper.
- Finely chop the dark chocolate and set aside.
- In a medium-sized bowl, whisk together the flour, cocoa powder, baking powder, and salt. Set aside.
- In the bowl of a stand mixer fitted with the paddle attachment, or a medium-sized bowl if using a handheld mixer, beat the butter and oil together until combined and completely homogeneous - this will only happen if the butter is completely at room temperature. About 2-3 minutes on high speed.
- With the mixer on low, slowly stream in the granulated sugar, then turn it up to medium-high speed and beat until light and fluffy. About 1-2 minutes, scraping down the sides and bottom of the bowl as necessary.
- Then, with the mixer on low, add the eggs in, one at a time, scraping down the sides and bottom of the bowl and mixing well in between each addition. Add the vanilla extract and mix on low until combined.
- Add half of the dry ingredients and mix on low until just combined. Add half of the milk, half of the coffee, and half of the sour cream and mix on low until just combined. Repeat this with the remaining halves of dry ingredients, milk, coffee and sour cream. Do not over-mix!
- Gently fold in the finely chopped chocolate in three additions.
- Separate the batter equally between the prepared pans (about 520 grams per pan) and spread it into an even layer. Bake the cakes for 25-32 minutes until a toothpick inserted into the center of the cake comes out clean. The cake will be slightly pulling away from the edges of the pan. Let the cakes sit in the pan for 10-15 minutes, then remove them onto a cooling rack to cool completely.
Milk Chocolate Ganache
- While the cakes are baking/cooling, make the ganache. Finely chop your chocolate and put it in a heat proof bowl. Set aside.
- Warm the heavy cream over the stove on medium heat until gently simmering and bubbles form at the edges of the pan. Pour the warmed heavy cream over the chopped chocolate and let sit for 3-4 minutes. The warmed heavy cream will melt the chocolate.
- Gently stir the cream and chocolate together until completely combined and smooth. Let the ganache cool at room temperature, stirring every 20 minutes or so, so the consistency remains the same throughout. It will thicken up to a buttercream texture.
- Cover tightly with plastic wrap until ready to use.
Chocolate Mascarpone Frosting
- In the bowl of a stand mixer fitted with the paddle attachment, or a large bowl if using a handheld mixer, beat the mascarpone and butter together on medium-high speed until combined, smooth and fluffy, and no more lumps exist. About 2 minutes.
- Add the vanilla extract, cocoa powder, one cup of the powdered sugar, and salt, and beat until combined - starting at low speed so the sugar doesn’t fly out of the bowl, then bumping it up to high speed. Continue to add one cup of powdered sugar add a time and repeat. Scrape down the bottom and sides of the bowl as necessary.
- If needed, add the milk then mix until combined. Once everything is combined, beat on medium speed for 2 minutes until fluffy. You may need to add more powdered sugar (to thicken) or more milk (to thin) depending on desired consistency.
- Once the cakes are completely cool, we can begin to assemble. Cakes are easier to assemble when they are slightly chilled, so feel free to put the cakes in the fridge for 20 minutes prior to assembling.
- If the cakes have formed a dome top, use a serrated knife or cake leveler to carefully level off the cakes.
- Put the mousse, ganache, and frosting in their own piping bags. This is not necessary, but I find it makes assembly much easier.
- Take the first cake layer and pipe a ring of the chocolate mascarpone frosting along the edge. Pipe about ⅓ of the thickened milk chocolate ganache in that ring, and smooth it into an even layer.
- Pipe the chocolate mousse on top of the ganache and spread into an even layer. Note: this recipe yields a lot of chocolate mousse, enough to put some in between each cake layer AND enough to dollop a bit of chocolate mousse on each individual slice of cake. So don’t feel like you need to use all of the chocolate mousse when assembling the cake.
- Place the second cake layer on top. Repeat the same process as above - pipe a ring of chocolate mascarpone frosting, spread another ⅓ of the ganache, then some of the mousse.
- Place the final cake layer on top. At this point, I like to put the cake in the fridge for 30 minutes so the cake layers and filling have time to firm up and set. This will make it easier to frost the rest of the cake - if the filling is warm, the cake layers may be unstable and slide all over the place.
- After the 30 minutes, make a crumb coat. Remove the cake from the fridge and frost the tops and sides with a thin layer of frosting. Place it back in the fridge for 30 minutes. This will lock in the crumbs so they don’t get mixed in with the frosting while you are decorating.
- Use the remaining frosting to frost the cake completely. Spread the final ⅓ of ganache on top of the cake. If it has thickened too much, microwave it for 5 seconds to loosen it up. If you have leftover frosting, use a star tip to pipe icing on the tops of the cake in any design you like!
- Top the fully assembled cake with mini chocolate chips or chocolate sprinkles. Slice and enjoy! Dollop some of the leftover mousse on the cut cake slices.
- Store the cake in an airtight container.
Tried this recipe? Make sure to rate and review and tag @sturbridgebakery on Instagram!