This Chocolate Mousse Cake is the definition of decadence! A single layer of moist chocolate cake is topped with light and fluffy chocolate mousse and the entire cake is covered in a rich shell of chocolate ganache. It's the perfect treat for any special occasion!
WHAT YOU NEED all purpose flour cornstarch dutch process cocoa powder baking soda baking powder kosher salt fine granulated sugar dark brown sugar vegetable or olive oil eggs vanilla extract sour cream hot coffee 70% dark chocolate milk chocolate unflavoured gelatin heavy cream cream of tartar
Chocolate Cake 1. Preheat the oven to 350F and grease the inside of a 9″ springform pan. 2. Then remove the ring, lay a sheet of parchment paper on the bottom plate, and close the ring on top. Some paper will be sticking out of the sides. 3. Now in a medium bowl, whisk together the flour, cornstarch, cocoa powder, baking soda, baking powder, and salt. Set aside. 4. In a large mixing bowl, whisk together the sugar, dark brown sugar and oil. It should look like wet sand. Then whisk in the eggs and vanilla, followed by the sour cream.
5. Dump in the dry ingredients and mix until it’s halfway combined. Then pour in the hot coffee and mix. 6. Pour into the prepared pan and bakevuntil a toothpick in the center comes out clean with a few moist crumbs. 7. Cool completely. Then, line the pan with a long sheet of acetate, sliding it down between the cake and the sides.
8. Stir together the hot coffee and cocoa powder. 9. Spoon the mixture over the cake, evenly soaking the entire surface. 10. Now set the cake aside while we make the mousse.
Chocolate Mousse 11. Add the chopped chocolate to a heat safe bowl. 12. Fill a saucepan with about 1/2 inch of water and place over medium heat. Then place the heat safe bowl on top, ensuring it does not touch the water. 13. Once simmering, the water below will slowly melt the chocolate. Stir until smooth then remove from heat. Allow the chocolate to cool slightly while you clean out the saucepan as we will be using it again. 14. After a few minutes, whisk 3 egg yolks into the chocolate mixture one at a time. The chocolate will thicken significantly, but that’s ok.
Chocolate Mousse 15. Now fill a tiny bowl with 3 tablespoons of water and sprinkle the gelatin on top. 16. Pour 3/4 cup of heavy cream into the cleaned saucepan and place it over medium-low heat. Heat just until it’s steaming but not bubbling. 17. By now, the gelatin should have bloomed. Scoop the gelatin into the steaming cream and whisk to melt. 18. Remove from heat and pour half of the cream into the chocolate and egg yolk mixture. Whisk until smooth, then whisk in the rest of the hot cream.
19. In a large bowl using a hand or stand mixer with the whisk attachment, add the remaining 1 cup of heavy cream. Whip on high speed until light and fluffy with stiff peaks. 20. Scoop the heavy cream into a smaller bowl and clean out the big mixing bowl and whisk. Make sure both are spotless and completely dry.
21. Now to that clean bowl, add the egg whites and cream of tartar. Whip on high speed. Once it starts to turns foamy and opaque, slowly whip in the fine sugar. Keep mixing on high speed until it turns white with soft peaks (pull the whisk away and if the meringue stands up with a little droop on the end, it’s perfect).
22. Using a rubber spatula, scoop the whipped cream into the chocolate mixture and gently fold to combine. 23. Scoop in the meringue and repeat the process. Keep folding until the mousse is all one color with zero white streaks. 24. Pour the mousse over the chocolate cake and chill in the refrigerator for at least 4 hours.
25. When the mousse has set, release the ring from the pan and peel back the cake collar. 26. For the ganache, add the chopped chocolate to a medium-sized heat safe bowl and the heavy cream to a heat safe measuring glass. Microwave the cream until it’s hot and bubbling. Pour the hot cream over the chocolate, ensuring the chocolate is completely submerged.
27. Allow to sit for about 3 minutes, then whisk to combine. 28. Pour the glossy ganache in the center of the cake and use a spoon or small overset spatula to spread it out towards the sides, allowing it to drip down. 29. Chill the cake for at least 30 minutes to allow the ganache to set. Then slice and enjoy!