Preheat the oven to 200 ° C (top / bottom heat). Separate eggs carefully. Beat the egg whites with a pinch of salt to form firm snow. Beat the egg yolks and sugar until creamy, then add the egg yolk and sugar mixture to the egg white and fold in. Mix flour and baking powder and carefully sieve on top of the batter mixture. Mix all ingredients with a spoon.
Line a springform pan with baking paper. Pour in the dough and place in the preheated oven for 20-25 minutes - do not open the oven door. Then place on a cake rack and cut in half to create a smooth surface.
Mix the crème fraîche with the sugar and place on the sponge cake base. Decorate with berries or fruit of your choice.
Tip: you can freeze the cut and leftover cake base and use it next time.