(Original in German: here)
150g soft butter, plus some more to grease the tin
1 teaspoon baking powder
grated zest of one lemon
Preheat the oven to 200°C.
Roast the nuts in a frying pan. Then, chop them. It works best if you shortly pulse them in a blender - this way, you get a nice mixture of finely and coarsely chopped nuts. Separate the eggs. Beat the egg whites until stiff, set aside.
In a bowl, beat sugar and butter with an electric hand mixer until pale and fluffy. Then, add ricotta, eggs and lemon zest. Beat until all is well combined and you have a smooth batter. In a separate bowl, mix flour and baking powder. Then add the flour to the butter mixture and beat well. After that, add the nuts and fold them in with a ladle. Then, carefully fold in the egg whites with a ladle.
Grease a large bundt tin (about 1.5l capacity) or two small ones with butter. Dust with flour. Then, fill in your batter. Bake your cake for about 50 minutes. If a wooden skewer inserted into the cake comes out clean, it's done.
Let cool in the tin for at least ten minutes before releasing the cake. I usually let it cool longer because I find that, when I try to release bundt cakes too early, I always destroy them. Dust with icing sugar before serving.