Put aside the cabbage. In a mixing bowl, mix by hand all the other ingredients, except sauce, and set aside. (This will be the filling to stuff the cabbage leaves.)
Core out the centers of the cabbage. Place the whole cored cabbage in a large pot of boiling water. Boil until the leaves become slightly transparent. (Savoy cabbage cooks very quickly). Remove leaves from the water, 1 at a time.
Preheat oven to 375 degrees F.
Roll the meat mixture into 2-inch balls. Elongate slightly and place on individual cabbage leaves. Starting from core edge, roll cabbage with meat inside and tuck in sides to complete rolling process. Place in a covered roaster pan with some water and cook for 1 1/2 hours.
Remove cooked cabbage rolls from roaster pan, and place on a serving plate. Serve with mushroom sauce over top.
In a saucepan, combine mushrooms and 4 cups water, and bring to a boil. Boil for about 10 minutes or until mushrooms are soft. In a mixing bowl, mix flour and sour cream with 1/2 cup cold water, whisking until blended. Add mixture to mushrooms, stirring until blended. Simmer, stirring, for 5 minutes. Season, to taste, with salt and pepper.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.