Bring a deep stock pot 1/3 full of water to a boil.

Core the cabbage head and carefully separate the leaves.

Thinly slice any remaining cabbage that couldn't be separated and add to the pot.

Stack the separated cabbage leaves in the boiling water and cover until pliable (5-15 minutes).

Remove cabbage leaves individually and cool to handling temperature.

Mix ground beef, rice, onion, eggs, and seasonings until moist and able to be shaped into a ball.

Roll approximately two ounces of the ground beef mixture into a ball and place onto a cabbage leaf, then roll it up.

Chill the cabbage rolls while preparing the sauce.

Cut the flanken into small strips or pieces.

Brown the flanken and onion in oil over medium/high heat.

Add in the sauerkraut and brown sugar.

Adjust the amount of brown sugar and sauerkraut to achieve the desired sweet/sour balance.

If the sauce is too sweet, add lemon juice or citric acid if sauerkraut is unavailable.

Add the tomatoes, tomato paste, and leftover sliced cabbage to the sauce.

Mix well and bring the sauce to a boil.

Carefully add the cabbage rolls in layers to the sauce.

Cover the pot and cook over low heat (simmering) for approximately 2 hours.

Serve with peeled boiled potatoes, mashed potatoes, or potato dumplings.