Chocolate Cookie Dough Layer Cake

For the Cake

• Preheat the oven to 350°. Prep 3 8-inch round cake pans by lining them with parchment paper and then spraying them with nonstick spray. Set aside.
  
• In a large mixing bowl, whisk together the cocoa powder and hot water. Add in the vegetable oil and vanilla. Whisk in the eggs and then the sour cream. Lastly, add in the sugar and whisk well to dissolve.
  
• In a separate, small bowl, mix together the flour, baking powder, baking soda and salt. Add the flour mixture into the wet mixture and whisk together just until the flour is incorporated.
  
• Evenly divide the cake batter into each of the prepared cake pans. Place into the oven to bake for 22-25 minutes or until a toothpick inserted comes out clean. Remove from the oven and place onto a cooling rack to cool to room temperature.
  
• While the cakes are cooling, make the cookie dough filling and the buttercream.
• Make the Cookie Dough: Combine the butter, brown sugar, and granulated sugar in the bowl of a stand mixer. Using a paddle attachment, beat on medium-high speed until the ingredients are creamed together. Add in the milk, vanilla, and salt and beat together. Add in the flour and mix. Fold in the mini chocolate chips. Set aside.
  
• Make the Buttercream: In the bowl of a stand mixer, combine all of the buttercream ingredients except the milk. Using a paddle or whisk attachment, beat first on low until the powdered sugar has incorporated. After about 3 minutes, turn the mixer up to high and beat for another minute. Add in the milk and beat on high for another 3 minutes.
  
• Once the cakes are cooled, place one layer onto a cake stand or a plate. Line the used cake pan with parchment paper. Place half of the cookie dough into the cake pan and evenly spread it out to fill the pan. Remove from the pan and place it on top of the bottom layer of cake. Place a second layer of cake on top of the cookie dough. Spread the second half of the cookie dough and place it on top of the second layer of cake. Place the last layer of cake on top.
  
• Fill a piping bag fitted with a piping tip with ¾ cup of buttercream. Spread the remaining buttercream around the sides and the top of the cake. Using an offset spatula, spread a thin layer of buttercream over the entire cake to seal any crumbs into place. Let set for 5-10 minutes so that a buttercream sets a little before spreading another layer of frosting on.
  
• To smooth the frosting, fill the bottom of a cake pan with warm water. Dip the offset spatula into the water and let most of the water drip off. Gently press the offset spatula parallel to the cake at a 45-degree angle and pull the frosting around the cake allowing a sort of wall to form at the top edge. Before wetting the spatula each time, remove any frosting from the back of the spatula and place back into the bowl. Dampen the spatula again and continue smoothing the sides. It may take several times around the cake to smooth it out. Once the sides are smooth, smooth the top by laying the spatula at the edge and gently pulling the frosting edge in towards the center of the cake. Once the frosting “wall” is smoothed out, smooth the rest of the top of the cake by laying the spatula at a 45-degree angle and turning the cake, pulling the frosting around and removing any excess. Remember to remove any frosting from the spatula before dampening it.
  
• To further decorate the sides, place mini chocolate chips in the palm of your hand and cup them close to the bottom of the cake. Gently press them into the sides. Pipe frosting onto the top of the cake. I like to pipe the frosting swirls in the formation of a clock. First pipe at “6:00” then “12:00” for good starting references. Then pipe at “3:00” and “9:00”. From there, each time you pipe a swirl, pipe another one directly opposite to it. This will help to have a perfect round circle of swirls.
  
• Slice and serve the cake!