Separate the leaves from the sauerkraut cabbage, rinse them thoroughly, then soak in water to reduce the sour taste. Set aside the smaller leaves.
Heat oil over low to medium heat and fry the diced bacon and onion until softened. Set aside.
In a large bowl, combine minced meat, fried bacon, onion, garlic, salt, pepper, and paprika. Add rice and 200 ml of stock, mixing everything well.
Place a cabbage leaf on a chopping board and trim the thick, stemmy middle part. Spoon about 1 tablespoon of filling onto the leaf, fold in the sides, and roll tightly:
Layer a few bacon slices as well as small or leftover cabbage leaves at the bottom of a large pot.
Carefully arrange cabbage rolls in the pot, add the remaining bacon slices and bay leaves, then cover with stock.
Place a large heatproof plate on top of the pot, cover it with a lid, and simmer over medium heat for 2-2½ hours.
Heat oil in a small pan, add flour and paprika and stir until golden. Mix in tomato paste and water, then simmer for 2-3 minutes. Add the roux (zaprška) to the pot during the last 30 minutes of cooking.
Let the Sarma rest for a few minutes before serving. Serve warm with mashed potatoes or your favorite side dishes.