Whip the egg whites until stiff and gradually fold in the sugar.

Add the yolks gently using a spatula, then fold in the flour.

Spread the mixture evenly on a baking sheet, dust with icing sugar, and bake at 170°C for about 10 minutes.

Alternative: For a round shape, bake in a savarin tin using the same method.

Beat the eggs in a stand mixer. Heat the sugar and water to 118°C, then slowly pour the syrup over the eggs while whisking.

Continue to beat until completely cooled, then add the butter little by little and finally the coffee extract or ristretto.

Layer the sponge and mocha buttercream alternately, lightly soaking each sponge layer with coffee.

Spread the buttercream over the entire cake and decorate with a smooth wave of vanilla whipped cream.