Remove the fermented dough from the container and grate it with a box grater or with a food processor. Stir in the spices and orange peel.
Put the egg yolk in a ramekin and stir the baker's ammonia into the yolk. In a separate ramekin, stir the potash together with the 2 tablespoons of water. Add them both to the dough.
Knead the dough until all the ingredients are well-combined. This may take a while if you are kneading it by hand. Add 1-2 tbsp. cold water if necessary. It helps to knead it on a very well-floured surface.
Roll out the dough to a thickness of about ¼" or 6 mm on a floured work surface. Cut out large hearts using cookie cutters.
Roll the remaining dough together and roll them out again, repeat the cutting until there is no more dough left.
Put the honey hearts on a baking sheet with baking paper and bake them in a preheated oven at 350℉ / 180 ℃ for about 10-12 minutes. Keep an eye on them. They should not turn brown. You can tell when they are done baking by pressing a finger down the middle. If no fingerprint is left, they are done.
Cool the hearts on a baking rack. When cooled, they are brittle and inedible. Spray a clean cloth with water and wrap the honey hearts, first in the lightly sprayed cloth and then in an airtight container or sealed freezer bag.
Refrigerate the honey hearts for 2-3 days, after which they will be delicious and soft and ready to be decorated and eaten. If they are not quite soft enough, sprinkle a little more water on the cloth and wait an extra day.