For the cake
1/2 cup unsweetened cocoa powder, sifted (45 g)
3/4 cup boiling water (180 ml)
1 3/4 cups all-purpose flour (210 g)
1 3/4 cups granulated sugar (315 g)
1 1/2 teaspoons baking soda
1 teaspoon salt
1/2 cup whole milk (120 ml)
7 large eggs, at room temperature, separated
2 tablespoons pure vanilla extract
1 teaspoon instant coffee powder
For the mousse
3 cups heavy cream (720 g)
1 1/2 cups confectioners' sugar (200 g)
3/4 cup unsweetened cocoa powder, sifted (65 g)
2 tablespoons pure vanilla extract
1 tablespoon white gelatin, unscented
2 tablespoons water
For the cake
1/2 cup unsweetened cocoa powder, sifted (45 g)
3/4 cup boiling water (180 ml)
1 3/4 cups all-purpose flour (210 g)
1 3/4 cups granulated sugar (315 g)
1 1/2 teaspoons baking soda
1 teaspoon salt
1/2 cup whole milk (120 ml)
7 large eggs, at room temperature, separated
2 tablespoons pure vanilla extract
1 teaspoon instant coffee powder
For the mousse
3 cups heavy cream (720 g)
1 1/2 cups confectioners' sugar (200 g)
3/4 cup unsweetened cocoa powder, sifted (65 g)
2 tablespoons pure vanilla extract
1 tablespoon white gelatin, unscented
2 tablespoons water
1
Prepare the cake: place the cocoa powder in a small bowl and add the boiling water
Mix until well dissolved and let it cool for 30 minutes
Preheat the oven to 350°F (moderate)
In a large mixing bowl, sift together the flour, sugar, baking soda, and salt
Make a depression in the center and add the milk, egg yolks, vanilla extract, and dissolved cocoa powder
Mix well with a wooden spoon
2
Dust the top of the cake with confectioners' sugar
3
Prepare the mousse: In a large mixing bowl, beat the heavy cream, confectioners' sugar, and unsweetened cocoa powder until firm
Let it chill for 1 hour
Sprinkle gelatin over the water and let it hydrate for a few minutes
Heat in a double boiler, stirring until dissolved. Reserve
4
Cut a lid from the cake, about 2.5 cm thick. Reserve
With a sharp knife, make a circular cavity in the center of the cake, maintaining a margin of 2.5 cm
Remove the core with a spoon
Reserve 1 1/2 cups of these crumbs from the cake
5
Mix 2 1/2 cups of the chocolate mousse and place it in a small bowl
Mix with the dissolved gelatin and fill the cavity of the cake
Replace the lid on the cake
Mix 1/2 cup of the mousse with the reserved crumbs from the cake and fill the center of the cake (the hole)
With the remaining mousse, cover the top and sides of the cake
Chill until serving time
571 calories per slice
