Chocolate Mousse Cake (Whoopie Pie Cake)

It’s Max’s birthday tomorrow and I’ve wanted to make a cake for him for some time now. I usually buy him a cake from Whole Foods, but it never has the right amount of ingredients. This cake was made specially for him based on ingredients and flavors he enjoys. I found a great Chocolate Cake Recipe online that was made on the Barefoot Contessa show, Beatty’s Chocolate Cake, Ina adds a chocolate buttercream layer and covers the cake with it, but I only wanted the chocolate cake part of her recipe. Max loved the Vanilla Mousse that I made some time ago and I thought that would be a great layer for the cake. He also loves chocolate ganache and I decided to add that between each layer and to top the cake off with it.



I stopped by Target a little earlier for a cake storage holder and found the perfect one with a locking lid and handle, I believe it’s Rubbermaid. The cake is now safely in the fridge and ready for its travels to dinner tomorrow. I hope you enjoy it as much as we do.

Here is the cake before I lit the candles, the nickname for the cake throughout the night was whoopie pie cake, and it sure did taste similar to one, but so much better.




  • For the Cake:
  • Butter, for greasing the pans
  • 1 3/4 cups all-purpose flour, plus more for pans
  • 2 cups sugar
  • 3/4 cups good cocoa powder
  • 2 teaspoons baking soda
  • 1 teaspoon baking powder
  • 1 teaspoon sea salt
  • 1 cup buttermilk, shaken
  • 1/2 cup vegetable oil (we used rice bran oil instead)
  • 2 extra-large eggs, at room temperature
  • 1 teaspoon pure vanilla extract
  • 1 cup freshly brewed hot coffee
  • For the filling (vanilla mascarpone mousse):
  • Half a cup of Mascarpone Cheese
  • One Vanilla Bean (seeds scraped from the pod)
  • Three tablespoons of sugar
  • 1 1/2 cups heavy cream
  • Two egg whites
  • Chocolate Ganache:
  • 1 1/2 cup of semisweet chocolate chips
  • 3/4 cup of heavy cream


  1. For the Cake:
  2. Preheat the oven to 350 degrees F. Butter two 8-inch x 2-inch round cake pans. Line with parchment paper, then butter and flour the parchment paper.
  3. Sift the flour, sugar, cocoa, baking soda, baking powder, and salt into the bowl of an electric mixer fitted with a paddle attachment and mix on low speed until combined. In another bowl, combine the buttermilk, oil, eggs, and vanilla. With the mixer on low speed, slowly add the wet ingredients to the dry. With mixer still on low, add the coffee and stir just to combine, scraping the bottom of the bowl with a rubber spatula. Pour the batter into the prepared pans, put a little more into one then the other, the one with the most batter will be cut in half later and the other one will remain as is. Bake for 35 to 40 minutes, until a cake tester comes out clean; make sure to test the one with the least amount of batter a little earlier since it will cook faster. Cool in the pans for 30 minutes, then turn them out onto a cooling rack and cool completely.
  4. As the cake cools, you can start on the mousse.
  5. For the mousse:
  6. In a bowl, whip the heavy cream, mascarpone cheese and vanilla bean seeds until soft peaks are formed. In another bowl, whip the egg whites into soft peaks. Once soft peaks are formed, gradually add the sugar and continue whipping until firm. Fold the egg mixture into the whipped cream mixture. Cover your mousse and put it in the fridge for about 30 minutes for it to set.
  7. Once your mousse sets, start your Chocolate Ganache:
  8. Place your chocolate chips and heavy cream in a glass (heat safe) bowl, set it over a pot of water set at a low simmer (double boiler). Stir until smooth and warm.
  9. Place 1 layer (the big one), flat side up and cut in half. On a flat plate or cake pedestal, place the flat side of the cake you just cut. With a knife or offset spatula, spread the top with chocolate ganache, then place half of your mousse on that. Place the second layer on top, rounded side up, and spread ganache on top followed by the rest of your mousse. Place your third layer on top, rounded side up, and spread the remaining of your ganache. Place your cake in the fridge for six hours or overnight.


I'm a lover of cooking, reading, ceramics, and travel.