Mix flour, salt, sugar, baking powder and vanillin sugar in a bowl. Add egg and butter in pieces. Quickly knead into a smooth dough. Cinnamon u
Form into 2 rolls (each approx. 36 cm long, approx. 3 cm Ø). Wrap in foil and chill for at least 2 hours. Cut each roll of dough into approx. 1 cm thick slices. Distribute on approx. 2 baking trays lined with baking paper. Bake one after the other in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 10-12 minutes. Let them cool down.