Prepare the cabbage. If using pickled cabbage, carefully separate the leaves and trim away thick ribs. Rinse briefly if the leaves are very salty or sour. If using fresh cabbage, follow the note below to soften the leaves.
Sauté the vegetables. Heat the oil in a skillet over medium heat. Add the onions and cook until softened. Stir in the grated carrot and celery root and cook for another 3–5 minutes. Add the rice. Stir in the uncooked rice and paprika. Cook for 1–2 minutes, then remove from the heat and allow the mixture to cool slightly.
Prepare the filling. In a large bowl, combine the ground meat, vegetable and rice mixture, tomato paste, thyme, black pepper, and fresh dill. Mix gently until evenly combined.
Fill and roll the leaves. Place a spoonful of filling near the bottom of each cabbage leaf. Fold in the sides and roll into a compact parcel, leaving a little room for the rice to expand.
Arrange in a pot or oven-safe dish. Spread chopped leftover cabbage across the bottom. Arrange the cabbage rolls in snug layers, with the folded edges facing down. Add the bay leaves.
Add the sauce. Pour the tomato passata over the rolls. Add enough water or unsalted stock to bring the liquid close to the top of the rolls.
Cook until tender. Choose either cooking method below.
Stovetop method: Cover the pot and bring the liquid to a gentle simmer. Reduce the heat to low and cook for approximately 1–1.5 hours. Check occasionally and add a little hot water if needed. Avoid vigorous boiling, which can tear the cabbage leaves. Oven method: Preheat the oven to 350°F (180°C). Cover the oven-safe pot or baking dish tightly with a lid or foil. Bake for approximately 1.5–2 hours, checking occasionally to ensure there is enough liquid. Add a little hot water if needed to prevent the rolls from drying out. Check and serve. The cabbage should be tender, the rice fully cooked, and the filling should reach a safe internal temperature of 160°F (71°C) for ground pork or beef. Allow the cabbage rolls to rest for a few minutes before serving.