Divide the cabbage into 4 pieces, place in the pot of lightly salted water, cook until soft.
While the cabbage is getting tender, peel the onions and chop them finely. Melt some butter and fry the onion slowly, season with salt and pepper.
Drain the cabbage and add to the frying pan. Mix with onions and fry together for 10 minutes on low heat.
Choose one of the dough recipes from here, or follow this basic recipe below.
Sift the flour onto your work surface. Make a well in the flour heap, pour in a small amount of hot water.
Knead together, gradually adding enough water, so that the dough to becomes elastic and soft. Avoid adding too much water - the dough will get too sticky.
Cut the dough into four parts. Spread one on your work top sprinkled lightly with flour.
Roll into a thin layer of dough. Cut it into circles using a glass or round cutter.
Place a spoonful of sweet cabbage filling in the middle of each circle. Fold dough over filling. Press edges together.
Continue forming pierogi until you're out of ingredients.
Bring a pot of salted water to a boil.
Reduce the heat, drop in a couple of pierogi, Cook until they start to float to the top (5-6 minutes).
Use a slotted spoon to collect the dumplings. Serve with melted butter or another topping of choice.