Mix spelt flour, ground almonds, brown sugar, vanilla sugar, cornstarch, salt, and cinnamon together in a mixing bowl. Mix melted butter and cashew butter in a separate mixing bowl.
Then mix the liquid into the dry ingredients. It is best to knead everything well with your hands.
Let the dough rest in the fridge for 1 hour.
In the meantime, sieve the icing sugar into a bowl and mix it with vanilla sugar.
Then roll the cookie dough and cut the rolls into slices. Shape the slices into crescents.
Do not place the vanilla crescents too close together on the baking paper. Bake the vanilla crescent cookies for 10 - 12 minutes.
Now let the cookies cool down shortly. Either you roll the vanilla crescents in the powdered sugar mixture or you use it to dust them from all sides. The vanilla crescents break easily when they are warm, so I think dusting is the easier option. By the way, the icing sugar does not stick well on cold vanilla crescent cookies.