Mix the eggs, milk, flour, baking powder, 1 teaspoon sugar and salt to a smooth batter. Let it soak for about 15 minutes. Stir in the mineral water.
Heat the fat in portions in a small, non-stick pan. Bake 8 thin crêpes one after the other from the dough until golden brown and keep warm.
Mix the quark with 1 tablespoon of sugar and the vanilla sugar. Peel the banana, dice finely and immediately drizzle with lemon juice and then fold into the quark. Fill the crepes with it and roll up.