Sift the icing sugar. Mix the fat in a mixing bowl until creamy. Gradually stir in icing sugar. Stir in the egg. Mix flour and vanillin sugar, sieve onto the fat mass and stir in.
Stir in the almonds. Fill one third of the dough into a piping bag with star-shaped spout (min. 10 mm Ø). Spray onto a baking tray lined with baking parchment approx. 7 cm large S-forms or approx. 7 cm long strips.
Whisk the egg whites and 2 tablespoons of water and spread thinly on the dough with a brush, sprinkle with sugar pearls. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 10 minutes until golden brown.
Spray the remaining thirds of the dough in the same way, one after the other, onto 2 more baking sheets lined with baking paper. Spread the dough and sprinkle it on top. Bake both trays in the same way one after the other. Let the shortbread cool down on cake racks.