Whip Egg Whites: Beat egg whites until stiff peaks form. Gradually add powdered sugar and beat until glossy. Reserve 4 tablespoons for the glaze.
Mix Dough: Fold remaining egg white mixture into ground almonds, hazelnuts, cinnamon, and vanilla sugar. Mix until a sticky dough forms.
Shape Cookies: Roll out dough to ¼-inch thickness between parchment paper. Cut out stars with a cookie cutter.
Glaze and Bake: Spread reserved meringue over each cookie. Bake at 300°F (150°C) for 15–18 minutes.
