To prepare the cake layers

1. Preheat the oven to 350 degrees. Grease three 8” round pans. Place parchment rounds in the bottom of each one for easy removal, if desired.
2. In the bowl of a stand mixer or in a large bowl, combine the dry ingredients until well dispersed, about 30 seconds. Add the softened butter and ¾ of the buttermilk to the dry ingredients. Keep the mixer on low until slightly combined and then increase to medium speed and beat for 2 minutes. Scrape down the sides of the bowl. Add the rest of the buttermilk and one egg and beat on low for 30 seconds to incorporate. Add the additional egg and the vanilla and beat for another 30 seconds. Scrape down the sides of the bowl and fold in any unincorporated batter.
3. Spread the batter evenly among the three pans and bake in the oven for 20-25 minutes. A toothpick inserted should come out clean. Allow to cool in the pan for 10 minutes and then remove from pan and remain cooling on a rack until room temperature. If you don’t plan to use the cakes immediately, wrap tightly in plastic wrap.

To prepare the soak

1. Combine the coffee and coffee liquor in a small bowl. Taste the mixture. If it doesn’t have a strong coffee flavor, you can sprinkle in some of the espresso powder for an extra punch of coffee. If you would prefer a more mild coffee flavor, this is not necessary.

To prepare the mascarpone whipped cream

1. In the bowl of a stand mixer or in a medium sized bowl, beat together the mascarpone cheese and cream cheese until combined and smooth, about 1-2 minutes. Scrape the sides of the bowl. Add the powdered sugar and Kahlua and beat briefly to combine. In a separate bowl, beat the heavy whipping cream until stiff peaks form. To do this, start the mixer on low and beat until the cream gets frothy. Increase the speed to high and beat until the whipping cream has barely thickened enough to stand up in straight peaks on its own. Fold the whipped cream into the mascarpone mixture until smooth.

To assemble the cake

1. Level all three cake layers using a serrated knife. (Note: I find it easiest to level cakes when they are still partially frozen.) Use a basting or pastry brush to “‘soak” each cake layer with the soak. Continue adding the coffee liquid to the cakes until they are well moistened, but not to where the coffee has dredged all the way through and has made the cake fall apart. You may not use all of the soak.
2. On top of one soaked cake layer, spread about 1-1/4-1-1/2 cups of the mascarpone whipped cream and smooth out the top. Add an additional cake layer on top and repeat this process. Add the final cake layer to the top of the cake and spread a generous amount of whipped cream on top. Continue frosting the sides as well.
3. You can allow the cake to chill and firm up in the fridge for a few hours if desired, or you can serve it immediately. I prefer to allow the cake to sit in the fridge so that the cake layers can continue to soften and soak up the coffee and the cream.
4. Prior to serving, use a sifter to sprinkle some cocoa powder on top of the cake.