How to make
Separate the egg whites from the yolks. To the yolks add 4 tbsp sugar and beat until whitened.
Beat the whites to snow with the remaining 4 tbsp sugar and baking powder. Combine the 2 mixtures carefully, stirring from the bottom going up so the whites don't deflate.
Add the flour to them gradually, while stirring slowly. Pour the resulting mixture onto a rectangular oven dish covered with baking paper and smooth out the top.
Bake in a preheated 430°F (220 °C) oven for about 25-30 min. while keeping an eye on it.
Once you take out the layer, let it cool a bit, smear it with the jam mixed with the walnuts and wrap it into a roll. Sprinkle with powdered sugar.
