Preheat the oven to 180 ° C. Sieve the flour onto the work surface. To press a hollow in the middle. Add the egg yolks, sugar, ground nuts and vanilla sugar. Spread the butter in flakes over it. Knead everything well with your hands. Let the dough rest for 1 hour.
Beat the egg white with the powdered sugar.
Roll out the dough and cut out round cookies with a drinking glass. Place a small blob of egg white in the middle and stick a hazelnut with it.
Bake at 180 ° for a good 10 minutes. The straw hats are ready when the protein cap shows the first light brown discolouration.