Mix 3 eggs with a pinch of salt until frothy. Mix in 75 g of flour with the tip of a knife, baking powder and 150 ml of milk. Let it soak for 20 minutes. Stir 5 tablespoons of mineral water into the batter.
Grease the pan with butter and bake 4-5 crepes.
Mix 300 g cream cheese with 2 L milk and 100 g crème fraiche. Add 1 teaspoon of horseradish and chives. Spread the cheese mixture on the crepes, slices of salmon on top. Roll up and chill.