Very Rich! Gateau au Chocolat for Adults

Coat the mold with butter and sprinkle with flour or line with parchment paper.
Put the finely-chopped chocolate and butter into a bowl to melt in a double boiler.
When the chocolate has melted completely, add the brandy or rum to mix in.
Put the egg yolk and sugar into a bowl.
Whisk well until white and thick.
Prepare another bowl to whisk the heavy cream until the mixture forms peaks.
Put it into Step 4's bowl to mix in.
Add the melted chocolate.
Mix with a whisk.
Sift the cocoa powder and stir up from the bottom like cutting with a spatula.
Preheat the oven to 160C.
Prepare another bowl to make a meringue.
Put the egg white and granulated sugar, whisk well until the mixture forms peaks.
Add the meringue into Step 7's bowl.
Mix everything well with a spatula.
Pour the batter into the mold.
Bake for 40-45 minutes at 160C.
Check with a skewer and when it comes out clean and it's done.
Just after baking, brush with brandy or rum using a pastry brush to give it an adult flavor.
When the cake has cooled, wrap it with plastic wrap to leave for 1-2 days.
The flavours should have soaked in and softened the cake by now.
(Keep it in the fridge during the summer)
Just before serving, sprinkle with caster sugar.
It looks nice.