Preparation

Sponge cake
Line a 14cm baking tray with parchment paper.
Beat the eggs and sugar together for about 15 minutes, until they triple in volume. Add sieved wheat and potato flour. Stir gently with a kitchen whisk, pour into the prepared pan and bake at 175°C for 40 minutes. Set aside until completely cooled. Cut into 4 layers.

Cream
Whip the cream with the mascarpone cheese until stiff, but not too stiff (so that the cream does not curdle when you add the filling). Gradually add the Lauretta blueberry cream, whilst continuing to stir very slowly. Stir gently until well blended.

Cream for decorating
Simmer the milk with the sugar and let it cool down. Beat the butter until light and fluffy. Add the cooled milk and sugar, one spoonful at a time, then gradually add the sieved milk powder, stirring continuously. Finally add a few drops of food colouring.

Assemble a layer cake
Soak the first layer of sponge cake in water with lemon, spread about 50g of blueberry cream 35% Lauretta, spread 1/3 of the mixed blueberry cream and place the second layer of sponge cake on top. Repeat these steps twice. Let the layer cake cool in the fridge for at least one hour. Then spread the cake with the cream for decorating and finish as desired.