Separate eggs. Beat the egg whites and 4 tablespoons of cold water with the whisk of the hand mixer until stiff, adding 125 g of sugar and salt. Add egg yolks and fold in. Mix flour, pudding powder and baking powder, sieve onto the egg foam and fold in carefully.
Line the bottom of a springform pan (26 cm Ø) with baking paper. Fill in sponge cake mixture and smooth it down. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 25-30 minutes. Let the sponge cake cool down in the tin for about 10 minutes, take it out and let it cool down on a cake rack for about 20 minutes.
Sponge cake base, hollow out except for an approx. 1 cm wide edge and a 1 cm thick base. Lift the base onto a cake plate. Pour cherry groats onto the sponge cake base, except for 2-3 tbsp.
Whip cream, 1 tablespoon sugar, vanilla sugar and espresso powder until stiff with the whisks of the hand mixer. Spread the espresso cream slightly dome-shaped on the filled sponge cake base and add the remaining cherry groats as a blob. Crumble the sponge cake pieces and sprinkle them on the cake. Dust with icing sugar