(*) Makes forty-five to fifty pieces at 5 cm ø Beat the butter with the sugar until light.
Finely grate the chocolate and mix it with the butter cream. Mix the egg and fold it in with the orange zest and salt. Sift in the flour. Quickly prepare everything into a smooth dough. Wrap in plastic wrap and chill for at least 120 minutes.
Roll out the dough on the lightly floured surface under cling film to a thickness of four to five mm. Remove the plastic wrap and cut out rounds of any size. Place them on a baking sheet lined with parchment paper with enough space between them.
Bake the Guetzli in the oven heated to 200 °C on the second rack from the bottom for ten minutes. Cool.
For the garnish, thinly peel the orange peel (only the yellow part!) and cut into very fine strips.
Mix powdered sugar and orange juice to a thick glaze. Brush the orange cookies with it. Decorate with the orange strips while still wet.
The Guetzli will keep fresh for 2-3 weeks in a well-sealed tin.