Preheat Oven: Preheat your oven to 140°C (285°F).
Whip Egg Whites: Using a stand mixer with the whisk attachment, beat egg whites until stiff peaks form. Incorporate Sugar: Gradually add the icing sugar, one tablespoon at a time, until glossy.
Reserve Glaze: Reserve 2 tablespoons of this mixture for the glaze.
Mix Dough: Add homemade vanilla Sugar, bitter almond, cinnamon, and half of the ground almonds, mix until combined. Knead Dough: Knead in the remaining almonds to form a dough.
Roll and Cut: Sprinkle icing sugar on your work surface and rolling pin to prevent sticking. Roll out the dough to ½ cm (¼ inch) thickness. Cut out stars using a cookie cutter and place them on a lined or greased baking tray. Dip the star-shaped cookie cutter in icing sugar between cuts to prevent sticking and make it easier to remove the shapes.
Arrange on a Tray: Place them on a lined or greased baking tray. Re-Roll Dough: This dough can be kneaded together and re-rolled multiple times. Continue to knead, roll, and cut out stars until all the dough is used up.
Prepare Glaze: Mix the reserved egg white mixture with water. Brush a thin layer onto each star.
Bake: Bake for 25–30 minutes. The cookies should feel slightly soft underneath when removed from the oven.
Cool: Let the cookies cool completely before storing in an airtight container.