Whip egg whites and salt in a bowl until stiff.

Carefully fold in walnuts, hazelnuts and sugar with a baking spoon. This should result into a somewhat crumbly dough.

Carefully roll out dough between two plastic foils to about 1cm. Cut out flower or circle shaped cookies with a cookie cutter (ca. Ø 3cm) and put them on a baking sheet.

Let the cookies to dry in the open for either 6 hours or overnight.

Preheat the oven at 180° C. Bake for 12 mins in the upper half of the oven. Take them out again to cool.

For the icing, mix the powdered sugar, Cointreau and water. With a knife spread the icing over the surface of the cooled cookies and decorate them with the walnut kernels. Let the icing dry.

Keep the cookies in a jar or a tin box and they’ll stay fresh for about 3 weeks.