White and Dark Cookies
Beat the butter with sugar and salt until foamy and creamy. Stir in the flour and knead well to a smooth dough.
Shape the dough into a log of about 3 cm (approximately 1¼ inches). Wrap the dough log in plastic wrap and chill for about 1 hour in the refrigerator.
Cut the log into about 5 mm thick slices, place on a baking sheet lined with parchment paper and bake in a preheated oven at 180°C (fan: 160°C, gas mark 2-3) (approximately 350°F) for about 10 minutes until light golden.
Mix the sugar and vanilla sugar together, and roll half of the cookies in it while still hot.
Chop the couverture and melt slowly in a bowl over hot water bath. Dip the remaining half of the cookies up to half into the melted couverture, place on parchment paper and leave to dry.