1. Add the butter, sugar, and orange zest to a large bowl and mix until well combined. Add the eggs and vanilla extract (the rum as well, if you want to use it) and mix on high until very light and fluffy. Combine ground hazelnuts, spelt flour, cinnamon, cardamom, cloves, and salt. Add to the large bowl and mix/knead to get a smooth dough. Wrap into plastic wrap and place in the fridge overnight.

2. Line two baking sheets with baking parchment and set aside. Roll out the dough between two sheets of baking parchment to a thickness of about 0.4 inches (1cm). Cut into 2 inches (5cm) wide strips and those strips into 0.4 inches (1cm) wide sticks – you should end up with sticks/bars of 0.4×2 inches. Place on the prepared baking sheets with some space in between and place once more in the fridge for about 30 minutes.

3. Preheat the oven to 350°F (180°C). Take the first baking sheet out of the fridge, brush the sticks/bars with some whisked egg, and bake for about 16-18 minutes. The Nuss-Stängeli should be nicely browned. Remove from the oven and bake the next batch. Let the sticks cool down on a wire rack. Store in a tin box in a cool place.