Dark Chocolate Mousse Cake

This might be my favorite chocolate cake recipe of all time. I made it in October and took it to work to share with my coworkers. It reminds me of a cake The Cheesecake Factory used to sell circa 2008. Sadly, the cake is no longer on their menu. This recipe is gently adapted from Not So Humble Pie.

cake ingredients.

  • 5 ½ c. granulated sugar
  • 2 tsp. salt
  • 1 ½ c. dutch processed cocoa powder
  • 2 tsp. baking soda
  • 2 c. boiling water
  • 2 c. canola or vegetable oil
  • 4 tsp. vanilla extract
  • 3 ½ c. all-purpose flour
  • 8 large egg yolks
  • 4 large eggs
  • ½ c. buttermilk
  • vegetable shortening
  • cocoa powder

cake directions.

  1. Preheat your oven to 350°F. Place a rack in the lower third of the oven and set a baking stone on it. (The stone helps the cake bake evenly and prevents domed tops. This trick really works!)
  2. You’ll need three 8″cake pans for this cake. Grease the pans with vegetable shortening and then line them with parchment (sides and bottom–this is a sticky cake) then grease the parchment and coat with cocoa powder.
  3. In a large sauce pan, combine the sugar, dutch processed cocoa, salt and baking soda. Stir with a whisk until combined and then slowly add the boiling water while whisking. This will bubble up a bit while the baking soda reacts with any remaining acidity in the dutch processed cocoa. Once throughly mixed, place the sauce pan over medium-high heat and bring back to a boil. Then remove from heat and allow to stand for a minimum of 10 minutes. This step makes the dutch processed cocoa even more alkaline, which darkens the color of the cake.
  4. Measure out the flour, buttermilk, and separate the eggs. (In Ms. Humble’s blog she recommends that you remove the stringy white chalaza from the yolks so that they do not appear as white scrambled egg bits in your black cake. I did not follow her advice and regretted it. The damn cake had spots!) Add the oil and vanilla to the bowl of your stand mixer with the paddle attachment.
  5. Add the chocolate mixture to your stand mixer and mix on low speed for about 20 seconds. Add the flour and continue to mix on low until combined. With a minimum amount of beating, add the egg yolks, eggs, vanilla and buttermilk. The batter will be very thin.
  6. Divide the batter between your pans and place in the oven on your baking stone(s). Bake for at least 60 minutes until the center of the cake springs back when you touch it. A toothpick inserted in the middle should come out mostly clean. Allow the cake to cool for 10 minutes on a wire rack. Run a thin knife around the edge of the cake to loosen and invert onto a cookie sheet lined with parchment.
  7. Allow to cool completely then wrap the rounds individually in plastic and place in the refrigerator to chill before assembling.

chocolate mousse filling ingredients.

  • 10 large egg yolks
  • 1 c. granulated sugar
  • ⅔ c. water
  • 16 oz bittersweet chocolate (preferably 66% cacao), finely chopped (I just use bittersweet chocolate chips)
  • 2 c. heavy cream, chilled

chocolate mousse filling directions.

  1. In a heat safe bowl, beat the eggs and sugar together until the mixture is uniform and light in color. Place over a double boiler and whisk until slightly thickened. A ribbon of the egg sugar mixture should flow back into the bowl when the whisk is lifted and the sugar should just be beginning to dissolve. Add the water and then continue to whisk over the simmering water until the mixture hits roughly 160°F and coats the back of a spoon. Remove from heat and add the finely chopped chocolate. Stir until the mixture becomes cool to the touch, roughly 10 minutes.
  2. Set the chocolate aside and beat the heavy cream to soft peaks. Fold the cream into the chocolate (this takes quite a while), then cover and chill for 4 hours before filling and frosting the cake.

cake assembly.

  1. If your cake layers have domes, level them. Split the cake layers into two (or three if your cake is really thick and you can hold a steady knife).
  2. Assemble your cake by placing one round onto your serving platter. Spread the mousse to form an even layer on top of the cake. Repeat with remaining layers and then frost the sides and top. Use your cake decorating genius to decorate the cake. I like to make a swirl around the entire cake. If I’m really trying to impress people I’ll pipe designs using a pastry bag. Place the cake in the refrigerator to keep cool and prepare any garnishes you’re using. I made chocolate curls for garnish using the Pioneer Woman’s method.
  3. Keep the cake chilled until ready to serve. Then allow to come to room temperature before cutting and serving. Store the cake in the refrigerator, covered to keep it from absorbing odors, for up to 5 days.

Recipe rating: 

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