Place cabbage heads in the freezer for three days to soften the leaves.

In a pot, bring water to a boil and cook rice until al dente, about 10-12 minutes. Drain and cool.

Heat olive oil in a skillet, sauté onions until translucent, add grated carrots, and cook for 2-3 more minutes.

In a bowl, combine ground beef, ground pork, cooked rice, sautéed onions, carrots, parsley, salt, and pepper. Mix well.

In another bowl, whisk chicken stock, crushed tomatoes, sour cream, salt, and pepper until smooth.

Remove thawed cabbage leaves, trim thick ribs, and lay them flat.

Place filling onto each leaf, roll tightly, and place seam-side down in a baking dish.

Layer a bit of sauce on the bottom, add half the rolls, sprinkle bay leaves, and drizzle with half the remaining sauce. Repeat with remaining rolls.

Cover with foil and bake in a preheated oven at 350°F for 1 hour. Remove foil and bake for an additional 30 minutes.

Let the rolls cool slightly before serving garnished with sour cream and fresh herbs.