Separate eggs. Beat the egg whites and 3 tablespoons of cold water with the whisks of the hand mixer until stiff. Finally, add 100 g sugar and salt. Beat the egg yolks one after the other. Mix flour, starch, almonds and baking powder, sieve onto the mixture and fold in. Put the sponge mixture on a baking tray (32 x 39 cm) lined with baking paper, smooth it down. Bake in the preheated oven, middle shelf (electric oven: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 10 minutes. Turn the sponge cake onto a tea towel sprinkled with a little sugar and carefully remove the baking paper. Roll up the sponge cake plate with the cloth and let it cool
Soak gelatine in cold water. Mix mascarpone, quark, vanillin sugar and 60 g sugar. Melt the squeezed gelatine in a small pot. Stir in 3 tablespoons of cream, then stir into the rest of the cream. Halve the cream. Mix espresso powder and 1 tsp. hot water and stir into one half of the cream. Chill both creams for about 15 minutes until they start to gel
Unroll the sponge roll. Spoon both creams onto the base, leaving about 1 cm free at the edges. Marble the cream slightly and roll up again. Chill the sponge roll for about 2 hours. Dust with cocoa before serving
waiting time approx. 3 hours