German Heidesand Cookies

With a handheld mixer, mix together soft butter, icing sugar, grated marzipan paste, vanilla sugar and grated lemon zest until creamy. Sift flour over the mixture and incorporate. Form a long pastry roll, about 4 cm (1.6 inches) thick. Halve the roll, wrap each half in plastic and refrigerate for several hours or overnight.

Preheat oven to 175ºC (350ºF). Line two baking trays with baking paper.

Whisk egg yolk with a fork and brush cookie logs all over. Place granulated sugar on a plate and coat the logs in sugar. Cut the logs into ½ cm (0.2 inch) slices. Place the slices on baking trays and bake for about 10–15 minutes until cookies are golden.