Put flour, sugar, vanilla sugar, salt, almonds, egg yolk and bitter almond oil in a mixing bowl. Grate the raw marzipan mixture on a coarse grater. Add cold fat in flakes. Knead everything into a smooth dough. Cover and let it rest in the fridge for about 1 hour. Roll out the dough on a floured work surface to a rectangle of about 40x35 cm. Cut diamonds of approx. 4.5x4.5 cm with a dough wheel.
Place on a baking tray lined with baking paper. Brush with egg white and sprinkle with almond flakes. Bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 15 minutes. Let cool down on a cake rack. Dust with icing sugar. Results in approx. 45 pieces
Working time approx. 30 minutes. Baked on a baking tray