Butter, syrup, and brown sugar are put in a pot. Heat over medium heat until just melted (be careful it doesn’t boil). Then remove from heat.
Mix all the spices (except potash) together with the peeled almonds, pistachios, flour, and orange zest.
Dissolve the potash in the juice from half an orange. Now pour it into the pot with the slightly cooled “butter mixture”.
Now add the dry ingredients and knead the dough well.
Place the dough in a bread tin lined with baking paper.
Place the dough in the fridge for at least 4 hours or overnight.
Remove the dough from the mold and cut it in half lengthwise. Then trim the edges so you get a square.
Cut the cookies into slices about 3 mm thick.
Place them on a baking sheet lined with baking paper.
Bake them for 8-10 minutes at 175 degrees Celsius (347 degrees Fahrenheit) fan oven (keep a close eye on them so they don't burn).