NOTE: It is SUPER IMPORTANT that all the room temperature ingredients listed above are room temperature and not cold so that the ingredients mix and incorporate correctly.
Heat oven to 335º F/168º C. Prepare cake pans with cake goop or another preferred pan release. I used three 8"x2" round cake pans. Use the cake batter calculator above this recipe card to adjust the recipe to your size cake pan. Optional: Line the bottom of the pan with parchment paper to prevent sticking from the chocolate chips.
In a large measuring cup combine the beer, espresso powder and vanilla. Whisk together and set aside.
In a large bowl, sift together the flour, cocoa powder, salt, baking powder and baking soda and set aside.
Place the softened butter in the bowl of a stand mixer with the paddle attachment. Cream until smooth and shiny. With the mixer on low, gradually sprinkle in the sugar. Mix on medium high until mixture is fluffy and almost white. About 3-5 minutes.
Reduce the speed back to low. Add your (ROOM TEMP) eggs one at a time. Let the egg incorporate fully before adding in the next egg to avoid breaking your batter. Add in your mayo and mix until combined.
With the mixer on low, add in 1/3 of your dry ingredients and mix until almost combined. Add in 1/3 of your liquid ingredients. Repeat the process two more times until everything is combined.
Fold in the mini chocolate chips and divide the cake batter into your cake pans. Bake for 40 - 45 minutes until a toothpick comes out cleanly but with a few sticky crumbs. Don't over bake.
Let your cakes cool in the pan for 10-15 minutes before turning out onto a cooling rack. Let fully cool then gently wrap in plastic wrap and chill until the cakes are firm enough to handle. You can flash chill in the freezer if you need to cool them quickly.