Put flour, 125 g sugar, vanillin sugar, salt, egg and fat in flakes into a mixing bowl. Knead first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Wrap in foil and chill for about 45 minutes. Wash lime with hot water and rub dry. Finely grate the peel. Mix peel and 100 g sugar.
Halve the dough and form it into a roll (32 cm long). Use a long ruler to shape each roll into a square stick (3 x 3 x 32 cm). Roll in lime sugar, press it down and put it in a cool place for about 1 hour. Then cut each stick into 1 cm thick slices and place on 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: level 3) for about 12 minutes. Place on a cake rack, allow to cool and pack in tins
waiting time approx. 2 hours