Whip the egg with the sugar for 5-7 minutes. Then add the flour and cocoa powder and gently fold in.

Pour the batter into a pan greased with butter and bake for 10-15 minutes. Check doneness with a skewer. Remove and let cool.

Soak the gelatin in water for 10 minutes. During this time, whip the sour cream with the sugar and vanilla essence, and melt the chocolate over a water bath.

Squeeze out the gelatin, add it to the milk, and warm it on the stove so the gelatin dissolves.

Pour the milk with the gelatin into the sour cream in a thin stream, continuing to whip with the mixer. Then add the cocoa powder and melted chocolate and whip everything once more. The mousse is ready.

Place the base in a pan (mine is 16 cm) and soak it with milk. Pour the mousse over the top.

Place the cake in the fridge for 4 hours, or in the freezer - it can take it. Then take it out and enjoy. Bon appetit!