Whip butter, sugar, brown sugar and salt with the whisk of the hand mixer until creamy white. Mix the flour and starch and fold into the butter mixture (only until the flour mixture is stirred in). Chill the dough for approx. 2 hours
Mix light and black sesame seeds. Form the dough into 3 equal-sized rolls (each approx. 3 cm Ø) and roll in sesame seeds. Best left to rest in the refrigerator overnight
Cut rolls into 5-7 mm thick slices. Place on 2 baking trays lined with baking paper. Bake one after the other in a preheated oven (electric cooker: 150 °C/ convection oven: 125 °C/ gas: level 1) for 15-18 minutes. Take out and let cool down. Pack into a well sealable tin
waiting time approx. 14 hours