Preheat oven to 350º F. Drain and rinse sauerkraut. In large saucepan, cook cabbage covered with water for 15 minutes or until leaves are tender. Rinse in cold water. Separate 14 leaves from head and drain well. To prepare filling: In large fry pan, brown ground beef over medium heat until done, stirring frequently to break up beef. Add mushrooms, onion, and green pepper; cover and cook until tender. In large mixing bowl, combine meat mixture with rice, sauerkraut, salt, and pepper; mix well. Divide mixture between leaves and roll up, tucking in all sides. Place in two even rows seam side down in greased 9- x 13-inch pan. To make sauce: In medium mixing bowl, combine crushed tomatoes, chicken stock, pepper, salt, sugar, and savory. Pour over cabbage roll-ups in pan. Bake uncovered for 40 to 45 minutes or until hot and tender. Makes 14 servings.