Blueberry Sheet Cake

Spring has sprung and I am here for all of the spring and summer berries, including fresh blueberries! The fresh blueberries in this fluffy blueberry sheet cake give every bite a bit of freshness, and when paired with the blueberry buttercream this cake is *mwah* chef’s kiss! The vanilla cake is super moist and studded with fresh blueberries, and the blueberry buttercream is incredibly luscious and creamy it basically melts in your mouth.

Why you will love this blueberry sheet cake

1. The cake. This cake was adapted from my Vanilla Bundt Cake recipe and it is soooo moist and fluffy! It has the best vanilla flavor and is studded with fresh blueberries (but not in an overwhelming way). When stored properly, this cake stays moist and fresh for days.
2. The blueberry buttercream. The blueberry buttercream can be made with any of your favorite store bought blueberry jams. It is whipped to fluffy perfection and is the best topping to this cake.
3. It’s easy to make. All you have to make is the cake and the buttercream and boom you are done. It is easier than a layer cake but just as delish.

Key ingredients

• All purpose flour: all purpose flour is the key to a fluffy and moist cake! This is where a kitchen scale is most important, but if you don’t have one, make sure to properly measure your flour using the spoon and level method.
• Leavener: we use baking soda in this recipe.
• Fats: the key fats in this recipe are the unsalted butter, vegetable oil, eggs, and whole milk. All of these ingredients add moisture to the cake. 
• Sugars: the sugar of choice in this cake is granulated sugar. We also use powdered sugar in the buttercream.
• Eggs: eggs add moisture and bind the ingredients together.
• Blueberries/blueberry jam: the star ingredient! We use fresh blueberries in the cake and your favorite store bought blueberry jam in the buttercream.

Steps

1. Prepare blueberries. Toss blueberries with one tablespoon of flour until evenly coated.
2. Whisk the dry ingredients. Whisk together the flour, baking soda, and salt.
3. Mix the wet ingredients. Beat together the butter and oil. Stream in the granulated sugar and mix. Add the eggs one at a time, mixing well in between each addition. Then add the vanilla extract and mix.
4. Combine. Add half of the dry ingredients to the wet ingredients and mix on low until almost fully incorporated. Then add half of the milk and mix on low until almost fully incorporated. Repeat this with the other halves of the dry ingredients and the milk.
5. Bake. Pour the batter into a 13×9 inch pan lined with parchment paper. Sprinkle the blueberries tossed with flour on top. Do not push them into the batter. Bake for 40-50 minutes at 350F until a toothpick inserted into the center of the cake comes out clean.
6. Make the blueberry frosting. Beat the butter until combined and fluffy. Add the vanilla extract, blueberry jam, salt, and one cup of the powdered sugar and beat until combined. Continue to add one cup of powdered sugar at a time and mix until combined. Add the milk if necessary and mix.
7. Frost. Once the cake is completely cool, frost the tops with the buttercream and enjoy! Store in an airtight container at room temperature.

FAQ

What types of blueberries should I use?

I prefer fresh. To be transparent, I haven’t tried frozen, but I imagine you can thaw them in the fridge and use them that way. Just make sure they are not super moist and mushy.

Why did my blueberries sink to the bottom of the cake?

1. Did you toss the blueberries in with the batter? This recipe specifically calls for sprinkling the blueberries on top of the batter before baking and not mixing them in. This will ensure they only sink about half way.
2. Did you toss the blueberries with flour? This helps coat them so they can more easily float throughout the batter when baking.
3. Did you use a kitchen scale to measure out all of your ingredients? When your mix-ins sink to the bottom of the cake, it is typically because the batter is not strong enough to hold the weight of whatever you are mixing in. If you did not use a kitchen scale, this could result in under measuring your flour or over measuring your liquids, and therefore the blueberries sank because they were too heavy for the batter.

Can I make the cake ahead of time?

Yes! Bake the cake and, once cool, place in the fridge to firm up for a few hours. Remove the cake from the pan and wrap the cake tightly in plastic wrap. You can freeze it for up to three months. Thaw the cake at room temperature. 

You can also make the 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 and once thawed, beat on medium speed to fluff it up. You may need to add 1-2 tablespoons of milk.

Why is my cake dry?

Cakes can be dry from over measuring the flour. The best way to measure flour is with a kitchen scale – it is the most accurate. If you don’t have a kitchen scale, spoon the flour into a measuring cup, then level it off with a knife.

Why did my cake sink?

Cakes can sink from over mixing the batter. Make sure to only mix your batter until the dry ingredients are JUST incorporated, not any longer. Second, an underbaked cake can sink, so make sure to bake the cake all the way through.

How do I store the cake?

Any cake-based dessert exposed to air will become dry pretty quickly, so make sure to secure it properly. I like to cut the cake into pieces and place in an airtight container, like a Tupperware, and store at room temperature.

Why is my frosting grainy?

Grainy frosting can be due to the butter being too cold or unsifted powdered sugar. In order to avoid grainy frosting, make sure to use room temperature ingredients and sift your powdered sugar if you notice it is clumpy. 

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

• Lemon Blueberry Buckle
• Twisted Blueberry Rolls
• Blueberry Muffins
• Vanilla Bundt Cake
• Small Batch Vanilla Cupcakes

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