A 21 cm (about 8 inches) springform pan.
Chocolate Biscuit:
3 eggs
½ cup sugar
8 tablespoons water
½ cup flour
2 tablespoons cocoa powder
½ teaspoon ammonia (baking ammonia)
Peanut Brittle:
50 g (about 3.5 tablespoons) butter
4-5 tablespoons sugar
100 g (about 3.5 oz) peanuts
Coffee Mousse:
500 ml (about 2 cups) heavy cream or sour cream
3 heaping tablespoons sweetened condensed milk
3-4 tablespoons sugar
2 tablespoons instant coffee
2.5 tablespoons gelatin
½ cup water
Chocolate Mousse:
200 ml (about ¾ cup) heavy cream or sour cream
1 tablespoon sugar
150 g (about 5.3 oz) chocolate
1 tablespoon gelatin
⅓ cup water
Chocolate Biscuit Preparation:
Separate the eggs into yolks and whites. Beat the egg whites with sugar until stiff peaks form (you can add a few grains of salt or a drop of lemon juice while beating). Then, continuing to beat with a mixer, add the yolks one at a time and pour in the water. Turn off the mixer. Sift the flour and cocoa into the bowl with the whipped eggs, add the ammonia, and gently fold everything together with a spoon until well combined. Line the bottom of the springform pan with greased parchment paper and pour the batter into the pan. Bake for 25-30 minutes at 180°C (about 350°F). Allow the biscuit to cool completely, then turn it out and remove the parchment paper. Line the sides of the springform pan with plastic wrap. Place the biscuit back into the pan.
Peanut Brittle Preparation:
The peanuts should be roasted and chopped. In a heavy-bottomed saucepan, combine the butter and sugar, and place it over low heat. Stir constantly to prevent burning until the butter and sugar are completely melted. Then add the chopped peanuts and continue stirring for another 2-3 minutes. Spread the mixture onto two plates in a thin layer, let it cool slightly (enough to handle), and break it into pieces while still warm. Evenly distribute the peanut brittle over the biscuit.
Coffee Mousse Preparation:
First, dissolve the gelatin. Boil the water. Pour the boiling water into a cup, add the gelatin and instant coffee, and stir until the gelatin is fully dissolved. Whip the cream or sour cream at room temperature (I used freshly made homemade sour cream) with sugar until it holds a shape but still flows slightly when tilting the bowl. Then add the sweetened condensed milk and mix with a mixer. Finally, add the dissolved gelatin with coffee and whip until thickened. Pour the coffee mousse over the brittle and smooth it out.
Chocolate Mousse Preparation:
Dissolve the gelatin. Boil the water. Pour the boiling water into a cup, add the gelatin, and stir until fully dissolved. Whip the cream or sour cream at room temperature with sugar. Melt the chocolate in a double boiler or microwave. Add the melted chocolate to the cream and mix well. Finally, add the dissolved gelatin and whip again until thickened. Pour the chocolate mousse over the coffee mousse and smooth it out carefully. Place the cake in the refrigerator for several hours to allow the mousse to set completely. Once set, remove the cake from the springform pan and decorate as desired.