Vanilla sponge cakes 

1. Preheat the oven to 350°F/180°C and prepare three 6inch/15 cm diameter cake pans by lining them with parchment paper on the bottom and sides.
2. Place the eggs, granulated sugar, and vanilla in the bowl of your stand mixer fitted with the paddle attachment and beat on high speed for 10 minutes until the mixture triples in volume.
3. Sift the flour and salt together and gently fold them into the mixture using a spatula until you have a smooth and homogeneous batter.
4. Pour the batter into the prepared 3 pans and bake in the oven for approximately 30 minutes (without opening the oven door) or until they are golden on top. Check the doneness by inserting a toothpick into the center of a cake; it should come out clean.
5. Let the sponge cakes cool for a few minutes in their pans before gently removing them by running a knife along the edges. Allow the sponge cakes to cool completely on a cake rack (you can gently trim the crusts with a knife if you want them to be completely white).
6. Cover the sponge cakes with plastic wrap and refrigerate them for at least 1 hour before assembling.

Mascarpone filling

• Place all ingredients in a large bowl: cold mascarpone, powdered sugar, full-fat heavy cream and vanilla extract.
• Whip with an electric mixer on speed 1 for about 2 minutes, until the mascarpone whipped cream is smooth and firm.

Assembling the layer cake 

1. Slice the sponge cakes using a cake leveler or a large serrated knife to have even layers.
2. Place the first layer of sponge cake on a rotating cake stand (on a cake board) and soak it with the cooled mixture of black coffee and sugar.
3. Top the sponge cake layer with a layer of mascarpone whipped cream, then sprinkle a layer of unsweetened cocoa powder on top.
4. Cover with the second layer of sponge cake and repeat the previous step until you reach the final layer of sponge cake.
5. Cover the entire cake with mascarpone whipped cream, decorate the top with the remaining whipped cream using a piping bag fitted with a round tip.
6. Decorate the top of the cake with unsweetened cocoa powder and refrigerate the cake for at least 1 hour before serving.