Finely chop the onion.

Saute chopped onion in a little oil with red paprika until softened.

Wash rice and drain excess water.

In a large bowl, mix ground chuck with rice, egg, cooked onion mixture, salt, and pepper.

Bring a large pot of water to a boil.

Carefully steam the head of cabbage, peeling off leaves as they become soft and pliable.

Trim the outer vein of each cabbage leaf for easier rolling.

Place a small amount of the meat mixture onto each cabbage leaf.

Roll the cabbage leaf tightly around the meat mixture to form a roll.

Stack the cabbage rolls into a large pot.

Pour in the sauerkraut and tomato sauce over the rolls.

Add 1/2 cup of water to the pot.

Bring the pot to a boil, then reduce heat to low.

Cover the pot and cook for 1 hour, or until the cabbage is very tender and the meat is cooked through.

Stir the pot periodically to prevent sticking.

Serve hot, garnished with sour cream.