For the sinuous wreaths, mix butter, sugar and flour into a dough.
When the dough is nice and firm, set aside part of it and add the grated chocolate to the other half.
Now take a piece of the light and the dark dough and tie it into a wreath. Brush with egg and sprinkle with coarse sugar. Do the same with the rest of the dough.
Bake the twisted wreaths in the oven until light yellow.