Chocolate sponge

1. Cream together the softened butter and icing sugar. Mix in the egg yolks one at a time.
2. Meanwhile, beat together the egg whites and granulated sugar to soft peaks.
3. Mix the lukewarm chocolate and flour into the butter mixture. Gently fold in the egg whites.
4. Spread the batter thinly in a baking sheet and bake in a 180° C (350° F) oven (160° C / 325° F convection oven) for about 15 minutes.

Vanilla cream

1. In a bowl, combine the yogurt, icing sugar, lemon juice and vanilla. 
2. Soak the gelatine in cold water; squeeze out well and dissolve in 50 ml (3 tbsp.) hot cream; stir into the yogurt mixture (1).
3. Finally, whip the remaining cream and gently fold into the mixture.

Presentation

1. Cut the cake into 5 x 10 cm (2 x 4") pieces.
2. Using a pastry pag, pipe a line of vanilla cream onto each rectangle (see photo).
3. Place a row of raspberries on the side.
4. Decorate with Florentine biscuits, if desired.