Filling: 200 ml of sweet-sour cream, 2 tablespoons of powdered sugar, 2 tablespoons of sour cream, chopped strawberries if desired.
1. Whisk the egg whites into a firm foam with the gradual addition of sugar. Finally, carefully mix the flour and add a teaspoon of lemon juice. Pour the mixture into a baking tray (approximately 2/3 of the oven tray) over the baking paper and sprinkle with finely chopped hazelnuts. Bake for 15 minutes in a preheated oven at 180 degrees until the crust is slightly browned.
2. Transfer the egg whites to a cloth sprinkled with powdered sugar and wrap the roll. When it cools, coat it with sweet sour cream filling and roll it up again. Allow cooling well to make it easier to cut.
3. For the filling, whisk the sweet cream as whipped cream, add sugar to taste, and finally mix in a few tablespoons of sour cream. You can also add little frozen berries as desired or strawberries.