1
Cook the Sauerkraut. Begin by simmering the sauerkraut in a large pot with the bay leaves, allspice berries, and water. Cover with a lid and let it cook for about an hour. After cooking, drain the sauerkraut, remove and discard the spices, then allow it to cool. Finely chop the sauerkraut.
2
Prepare the Mushrooms and Onions. While the sauerkraut is simmering, heat 2 tablespoons of oil in a medium-sized frying pan. Add the onions and cook over medium heat until they start to soften, about 5 minutes. Then, add the mushrooms, increase the heat, and cook until they are browned and fully cooked. Finish by stirring in 1 teaspoon of butter, and season with salt and black pepper to taste.
3
Combine Filling Ingredients. Combine the chopped sauerkraut with the cooked mushrooms and onions. Adjust the seasoning to achieve a balance of salty, sour, and a hint of sweetness from the onions.
4
Prepare the Yeast Mixture. In a small saucepan, gently heat the milk and butter until the butter melts. Transfer this mixture to another container and add 3 tablespoons of cold water to cool it down. Dissolve the fresh yeast in this mixture and set it aside.
5
Make the Dough. In a large mixing bowl, combine the flour, a pinch of salt, and sugar. Add the yeast mixture and 2 eggs. Mix until well combined. The dough will be sticky; avoid adding extra flour. Let the dough prove in the bowl until it triples in size, which should take about 1 to 1.5 hours.
6
Assembling and Baking. Once the dough has risen, preheat the oven to 165°C (330°F). Divide the dough into 10 equal portions, each weighing about 85 g. Roll each portion into a 16 cm (6 inch) square. Make five 3 cm cuts on both the left and right sides of the square. Place about 80 g of filling in the centre of each square. Braid the dough by alternating strips from each side over the filling. Brush each pasty with beaten egg and sprinkle with caraway seeds.
7
Bake. Bake the pasties on a baking tray lined with parchment paper for about 20 minutes. They may need to be baked in batches or on separate trays to ensure enough space for expansion.
8
Cool and Serve. Once baked, transfer the pasties to a cooling rack. They are best warm. To reheat them, a low oven or a covered dry pan over the lowest heat keeps the pastry better than the microwave does. Serve with a cup of beetroot soup. Enjoy your homemade Kapuśniaczki!