Bring a large pot of water to a gentle boil. Carefully remove the core from the cabbage and submerge it whole. As the outer leaves soften, peel them away one by one. Set aside 12 large leaves and chop any remaining cabbage finely for later use before moving on to the filling.

In a large bowl, combine minced pork, rice, onion, garlic, sweet paprika, hot paprika if using, salt, pepper, and egg. Mix gently with your hands until evenly combined, ensuring the rice is well distributed before shaping the rolls.

Place a spoonful of filling at the base of each cabbage leaf. Fold in the sides and roll firmly but not tightly to allow the rice room to expand. Continue until all rolls are formed, then prepare the cooking base.

Heat goose fat or lard in a heavy based pot. Add diced smoked bacon and cook until lightly golden. Scatter in chopped cabbage and half of the sauerkraut, creating a flavourful cushion for the rolls before layering.

Place the cabbage rolls seam side down in a snug single layer over the sauerkraut. Add bay leaves, then cover with the remaining sauerkraut. This layering protects the rolls and infuses them with gentle acidity during cooking.

Pour in enough stock to just cover the contents. Bring to a low simmer, cover with a lid, and cook gently for 90 minutes. Avoid boiling, as slow heat keeps the rolls tender and intact before thickening.

In a small pan, heat a little fat, stir in flour, and cook until lightly golden. Remove from heat and stir in sweet paprika. Loosen with a ladle of hot cooking liquid to prevent lumps before adding to the pot.

Gently stir the roux into the pot. Simmer uncovered for a further 15 minutes until the sauce lightly thickens and coats the cabbage rolls, then prepare to serve.

Serve hot with a generous spoon of sour cream on top. Töltött káposzta pairs well with crusty bread and improves after resting, making leftovers especially prized.