Preheat the oven to 180°C (350°F). Grease the cake pan with 10 g butter and dust it with 10 g all-purpose flour, then shake out the excess.

Separate the 4 eggs into whites and yolks. Beat the egg whites with the electric hand mixer until stiff peaks form.

Beat the 4 egg yolks with 100 g granulated sugar until pale and smooth. Melt 100 g baking chocolate with 200 g butter, then stir it into the yolk mixture.

Add 32 g all-purpose flour and 10 g baking powder. Mix until the batter is smooth and no dry flour remains.

Fold the beaten egg whites gently into the chocolate batter. Stop folding as soon as the mixture is evenly combined.

Pour the batter into the prepared cake pan. Bake for about 20 minutes, until a toothpick comes out nearly dry.

Pierce the warm cake all over with a fork. Leave the cake in its pan while preparing the ganache.

Heat 500 ml heavy whipping cream in a saucepan until it just reaches a boil. Pour the hot cream over 200 g dark chocolate.

Whisk the ganache until the chocolate melts and becomes smooth. Let it cool for 5 minutes.

Pour the ganache evenly over the pierced warm cake. Refrigerate the cake overnight before serving.

Put in the fridge overnight.