These chocolate stuffed sandwich cookies are too good. Two shortbread cookies are sandwiched together with a chocolate buttercream frosting. They are perfectly bite sized and super easy to make.
In the bowl of a stand mixer fitted with the paddle attachment, or using a handheld mixer, beat the butter and sugar together on medium-high speed until light and fluffy.
Add the egg yolks and vanilla extract and mix on medium speed until combined, scraping down the bottom and sides of the bowl if necessary.
Add the flour and salt and beat on low-medium speed until a dough forms. The dough will be thick. Turn the dough out of the bowl and shape it into a log. Wrap it in cling wrap and refrigerate the dough for one hour.
Once the dough has chilled for an hour, preheat your oven to 350 degrees and line a baking sheet with parchment paper.
Unwrap the dough and place it on a lightly floured surface. Roll the dough out until it is about ¼ inch thick. Use a small circular cookie cutter to cut out the cookies, placing them on the baking sheet about an inch apart. They will not spread much. Repeat this process with the remaining dough.
Bake for 9-11 minutes or until LIGHTLY golden. Remove from the oven and let them cool for 5 minutes on the pan, then transfer them to a cooling rack to cool compltely.
Chocolate Buttercream
While the cookies are baking and cooling, make the buttercream. In the bowl of a stand mixer using the paddle attachment, or using a handheld mixer, beat the butter until light and fluffy. Add the powdered sugar, cocoa powder and salt and mix on low speed for 30 seconds and then mix on high speed until completely combined.
Add 3-4 tablespoons of milk/heavy cream tablespoon by tablespoon until you get your desired consistency.
Assembling the Cookies
Once the cookies are completely cool, dollop or pipe a bit of buttercream over the backside of one cookie. Place a second cookie on top and sandwich together. Repeat with the rest of the cookies. Enjoy!