Based on my viral four layer chocolate mousse cake, this 9-inch, one layer chocolate mousse cake is simplified, made without raw egg, and just as decadent! It consists of a classic chocolate cake base, light & airy chocolate mousse, and rich & creamy chocolate ganache. It’s rich, silky, and light all at the same time, which is why it’s truly one of my favorite recipes I’ve ever created!
Preheat the oven to 350 degrees F and line a 9" springform pan with parchment paper.
In a medium bowl, whisk together the flour, sugar, cocoa powders, baking powder, and salt. Set aside.
In a large bowl, whisk together the milk, oil, eggs, and vanilla.
Add the dry ingredients to the wet and whisk until just combined.
Lastly, whisk in the hot coffee/espresso until fully combined.
Pour the cake batter into the prepared pan. Bake for about 35 minutes or until a toothpick inserted comes out clean.
Allow the cake to cool in the pan completely. Cover with plastic wrap and set aside until ready to assemble.
For the chocolate mousse:
In a large bowl, add the chocolate and set aside.
In a small saucepan, bring the whole milk, 42g (3 tbsp) heavy cream, egg, sugar, and salt to just shy of a simmer (180 F).
Pour the anglaise base through a fine mesh sieve over the chocolate, weighing the anglaise out to 180g, and mix until smooth (use an immersion blender for best results). Set aside to cool slightly.
In a separate small bowl, add the remaining 270g (1 cup + 3 tbsp) heavy cream and use an electric mixer to beat until stiff peaks form.
Add the whipped cream to the chocolate mixture in two parts and gently fold with a rubber spatula until fully combined.
Wrap an acetate cake collar around the outside of the cake (between the cake and the wall of the springform pan), then pour the mousse over the cooled cake and spread into an even layer. Chill the cake for at least 6 hours or overnight.
For the chocolate ganache:
In a small saucepan, bring the heavy cream to a simmer (or about 190 degrees F), then remove from heat, add the chocolate and butter, and mix until smooth.
Pour the warm ganache over the chilled cake and spread into an even layer.
Place the cake in the fridge uncovered and chill for about one hour or until set before serving.