Mix the butter and powdered sugar until frothy. Cut the vanilla pods lengthways. Scrape out the pulp and stir in. Mix the flour and cornstarch, add to the butter mixture and work everything into a smooth dough. Then shape into 3 cm thick rolls and refrigerate for 30 minutes.
Preheat the electric oven to 175 degrees. Cover the baking sheet with parchment paper. Cut the rolls into slices. Shape the slices into small balls and press each surface into a fine wire sieve. Place balls on the tray. Bake in the preheated oven for 12 minutes (gas: level 2).
Dust the cooled balls thickly with powdered sugar.