Stuffed Cabbage

Name: Stuffed Cabbage
Ingredients: 2 quarts water; 1 large green cabbage (about 2 ½ pounds); 2 tablespoons unsalted butter; 1 large onion, chopped; 1 garlic clove, finely chopped; 2 cups cooked rice; 8 ounces ground beef; 8 ounces ground pork; Coarse salt and freshly ground pepper; 1 tablespoon dried parsley flakes; 1 medium green pepper, grated; 2 celery stalks with leaves, finely chopped; 4 cups tomato puree; 1 Granny Smith apple, peeled, cored, and chopped; ½ cup sour cream, plus more for garnish