This is my own version inspired by recipes of several other people

Ingredients:

Sauce:

1 large onion diced

1 large carrot

2 celery stalks sliced

3 garlic cloves smashed

Olive oil

Bacon or pancetta (for rendered fat)

1 cup white wine

1 28 -29 oz. can tomato sauce

2 cups chicken stock

2 bay leaves

1 bundle thyme

Kosher salt

Cabbage and Stuffing:

¼ cup red wine vinegar

1 large head savoy cabbage, leaves removed, with hard bottom ribs discarded

Olive oil

1 large onion diced

Salt

3 garlic cloves smashed and minced

1 pound veal, pork, and beef meatloaf mix

1 egg

½  – ¾ cup raw white rice

2 sprigs fresh rosemary leaves finely chopped

½-1 cup chicken stock

1 cup or 1 small can sauerkraut

1 hot pepper whole –serrano, red chile, etc.

To make the sauce:

Puree the onions, carrots, celery and garlic to a paste-like consistency.  Add olive oil to a large pan and heat on medium adding bacon or pancetta strips to the oil, and cook until crisp and fat is rendered. Remove meat and add the pureed vegetable paste, cooking until soft and beginning to brown—about 10 minutes. Add white wine, stirring and allow it to reduce by half.  Add tomato sauce, chicken stock, baby leaves and thyme.  Add salt to taste.  Bring to a boil, reduce heat, and simmer for 15 minutes.

Prepare the cabbage:

Add vinegar to a large pot of salted water and bring it to a boil over medium heat.  Prepare a bowl of salted ice water on the side.  Add cabbage pieces no more than 3 at a time to the boiling water, and cook until softened, about 3-4 minutes.  Remove from pot and immediately put leaves into ice water.  When leaves are cool, remove from water and pat dry.  Put aside.

Meat stuffing:

In a large saute pan, heat olive oil over medium heat. Add onions and season with salt, cooking until they are translucent and aromatic.  Do not brown or burn.  Add the garlic and cook for 2 to 3 minutes more.  Turn off the heat and allow to cool.

Combine the ground meatloaf mix in a large bowl with egg, rosemary, and rice.  Season with salt and pepper.  Add chicken stock and cooked onions and garlic.  Mix with clean hands. Make a small tester patty to cook and eat. Adjust seasoning if necessary. 

Lay each cabbage leaf on a clean, flat work surface.  Place approximately ¼ cup of meat filling into center of the leaf.  Fold the outside edges in and roll the leaf around the stuffing.  Place seam side down in a large Dutch oven or crock pot with the sauce in the bottom.  Pour drained sauerkraut over the rolls and add the whole pepper to the pot, and cover.

Place the Dutch oven into a preheated 350-degree oven and cook for 1-1/2 hours. 
Cook in Crock pot on low 6-7 hours or on high 4-5 hours. 
Filling should reach a temperature of 160 degrees. 

Serve with crusty bread and sour cream.