Rinse the rice and cook it in salted water for about 10–12 minutes, until just tender rather than soft. Drain thoroughly and cool before mixing it with the meat.

Cut out the hard cabbage core and place the cabbage core-side down in a large pot of boiling salted water. As the outer leaves soften, remove them with tongs until you have about 16 usable leaves.

Trim the thick rib from the underside of each leaf so it bends easily. Reserve small inner leaves and torn pieces for lining the baking dish or covering the rolls.

Combine the cooled rice, ground pork, ground beef, chopped onion, egg, 1 teaspoon kosher salt, pepper, and marjoram. Mix gently just until combined, adding up to 1/2 cup water or beef stock if the filling seems dry.

For the sauce, sauté the chopped onion in butter or oil for about 5 minutes, until translucent. Add the crushed tomatoes, tomato sauce, stock, optional sugar, remaining salt, and pepper, then simmer for 10 minutes.

Place 2–3 tablespoons of filling near the lower edge of each cabbage leaf. Fold the sides inward and roll toward the top like a small burrito, keeping the filling enclosed without packing it too tightly.

Spread some tomato sauce in the bottom of a deep baking dish or Dutch oven. Arrange the cabbage rolls seam-side down in one or two layers, pour the remaining sauce over them, and add stock if they are not nearly covered.

Cover the dish tightly with a lid or foil and bake at 350°F (175°C) for 75–90 minutes. The gołąbki are ready when the meat is fully cooked, the cabbage is tender, and the rice is soft.

Let the rolls rest for 10–15 minutes before serving. Spoon extra tomato sauce over each portion and finish with sour cream if desired.