Chocolate Mousse Cake

Note: while there are multiple steps to this recipe, this dish is broken down into workable categories to help you better plan for preparation and cooking.

Make the Cake

1. Gather the ingredients.

   

2. Preheat the oven to 350 F and prepare a 9” springform cake pan. Place the springform pan on top of two pieces of parchment paper and trace a 9” circle. Cut the circles out. Reserve one circle for the assembly portion of the recipe. Flip the other circle over so any remaining marks from the pen will be on the bottom. Grease the bottom and sides of the pan with cooking spray. Place the parchment circle in the bottom of the pan. Set aside. 

   

3. Sift together the cake flour and cocoa powder into a large bowl.

   

4. Add the baking soda and salt, whisk together, and set aside.

   

5. Combine the butter and brown sugar in a stand mixer bowl fitted with paddle attachment. Paddle until smooth and homogenous.

   

6. Add the eggs one at a time, beating each one in until fully incorporated and scraping down the sides of the bowl before each addition. Continue to mix on medium speed until fully combined.

   

7. With the mixer off, add the vanilla extract and one-third of the sifted cake flour mixture.

   

8. Turn the mixer back on low speed and mix until just barely combined. Add half of the sour cream and paddle until just combined.

   

9. Repeat steps 7 and 8 until all the flour mixture and sour cream have been used up, ending with the flour mixture.

   

10. With the mixer off, scrape down the sides of the bowl. Turn the mixer back on low speed and slowly drizzle in the coffee. Mix until you have a smooth, satiny, and homogenous cake batter.

    

11. Pour the batter into the prepared springform pan and bake for 25-28 minutes. The cake is done when it springs back to the touch and pulls away from the sides of the pan. Let the cake completely cool at room temperature, then carefully remove the cake layer from the pan, peel off the parchment, and wrap the cake in plastic wrap. Place the cake in the freezer for at least 30 minutes. This will make it easier to slice the top off and create an even layer. Meanwhile, wash the springform pan and make the chocolate mousse.

    

Make the Mousse

1. Gather the ingredients.

   

2. Make a double boiler by adding 2-3 inches of water to a medium pot and bring to a boil. Place the chocolate in a large heat proof bowl. The bowl should be big enough so that it sits on the rim of the pot without touching the water.

   

3. When the water comes to a boil turn the heat all the way down. Stir the chocolate occasionally until it is about 75% melted. Then remove the bowl from the pot and stir the chocolate to finish melting it. Reserve the double boiler for making the glaze.

   

4. Whip the heavy cream in a stand mixer bowl fitted with the whisk attachment until it forms soft-medium peaks. Turn the mixer off and transfer the whipped cream into another bowl and refrigerate for later use.

   

5. Rinse and dry the bowl and whisk attachment and add the eggs and yolks to the bowl.

   

6. If using gelatin, pour 1 ½ tablespoons water into a small dish. Lightly sprinkle the gelatin over the water to bloom. Set aside until step 11. If not using gelatin, ignore this step.

   

7. Add the sugar and water to a small pot.

   

8. Make sure the pot and your hands are clean so the sugar doesn’t crystallize. Use your fingers to lightly swirl the sugar and water together. Place on the stovetop over medium-high heat and cook the syrup until it reaches 248 F.

   

9. While the sugar syrup is cooking, start whisking the eggs and yolks on medium speed until light and fluffy, 3 to 5 minutes. If the syrup is close to reaching 248 F but the eggs are not fluffy yet, take the syrup off the heat until the eggs are ready, then proceed to heat the syrup to 248 F. The whipped eggs will hold for a few minutes, but the syrup is very time-sensitive.

   

10. Once the sugar syrup has reached 248 F, with the mixer running slowly pour the syrup down the side of the bowl into the whisked eggs. Continue to whisk on medium high speed until it becomes even lighter and fluffier.

    

11. If using the gelatin, turn the speed down to low and add the bloomed gelatin. Continue to whisk until the bowl is barely warm to the touch.

    

12. Turn the mixer off and pour in the melted chocolate. Fold it into the egg mixture by hand using a silicone spatula.

    

13. Take the whipped cream out of the fridge and carefully fold that in. Try not to deflate the mousse.

    

Make the Glaze

1. Gather the ingredients.

   Note: This glaze can be made in advance, cooled to room temperature, then refrigerated in an airtight container for up to 2 weeks. Alternatively, wait until the mousse has chilled and set to make the glaze and use it right away.

   

2. Place the double boiler back on the stovetop, and heat the water until boiling. In a large heat-proof bowl, combine the butter and chocolate. Place over the pot to melt.

   

3. Once the water is boiling, turn the heat all the way down. Continue to melt until it is about 80 percent melted, then remove from heat and whisk until completely melted.

   

4. Add the corn syrup, and whisk again until completely smooth and streak free. Set aside.

   

Assemble the Cake

1. Remove the cake from the freezer. Unwrap it and use a serrated knife to slice the top dome off to create an even cake layer.

   

2. Prepare the springform pan. Place the reserved parchment circle on the bottom of the pan.

   

3. Cut another strip of parchment that is long enough to go around the inner circumference of the pan. The height of the parchment strip should be at least the same height as the pan. Place it inside the pan and tape the strip to form a loop.

   

4. Place the cake layer at the bottom of the pan.

   

5. Pour the mousse on top of the cake layer. Use a small offset spatula to smooth the top. Place the whole pan in the fridge for at least 6 hours to overnight to set.

   

6. Once the mousse is set, remove from the fridge. Prepare a wire rack set over a sheet of parchment paper on your work surface.

   

7. Unmold the cake and carefully peel off the parchment papers. Place the cake on top of the wire rack for glazing.

   

8. If the glaze was made in advance you will need to reheat it so it’s pourable. Heat in the microwave at 50% strength in 30 second increments, stirring after each time until the glaze is pourable and smooth but not hot. Pour the glaze over the cake, starting from the center working outwards in a circular motion until it drips over the sides completely enrobing the whole thing. Pick up the sides of the wire rack and lightly tap on the surface to even it out and shake off any excess.

   

9. Use a large offset spatula to carefully pick the cake up and place onto your serving platter. Refrigerate until ready to serve.