For the vanilla crescents, crumble butter with flour and quickly knead with the remaining ingredients to form a smooth shortcrust pastry. Wrap the dough in cling film and refrigerate overnight.
Then form thin rolls, cut into evenly long pieces and shape into croissants. Line a baking tray with baking paper, place the croissants on it and bake in a preheated oven at 190 °C for 10 minutes.
Mix the powdered sugar and vanilla sugar and roll the vanilla crescents in it while they are still warm.