Melt the butter and let it cool down.
Place the eggs and 125 g sugar in a mixing bowl and whisk with the whisk of the hand mixer for 3-4 minutes until creamy. Mix flour and baking powder, sieve onto the egg mixture and fold in. Gradually fold in first the milk, then the liquid butter. Put the dough into a greased springform pan (24 cm Ø) sprinkled with breadcrumbs and smooth it down.
Bake in the preheated oven, 2nd shelf from below (electric oven: 175 °C/ convection oven: 150 °C/ gas: level 2) for 30-35 minutes. Let the base cool down in the pan on a cake rack. Remove the base from the pan and cut through horizontally twice.
Soak gelatine in cold water for about 5 minutes, squeeze out. Heat 100 ml water, soluble coffee powder and gelatine over low heat while stirring until gelatine and coffee powder have dissolved. Stir in liqueur.
Whip the cream until stiff and chill. Whisk egg yolks and 175 g sugar with the whisk of the hand mixer for 3-4 minutes until creamy. Stir in mascarpone briefly, then fold in cream.
Place the bottom cake layer in the clean springform pan and sprinkle with some coffee mixture. Then spread with 1/3 of the cream. Repeat this procedure with the second and third cake base.
Chill the cake. 1 1/2 hours before serving, place the cake in the freezer. Remove the cake from the tin immediately, lift it onto a cake plate and dust with cocoa and possibly some icing sugar. Serve immediately decorated with physalis or other exotic fruits.