Spinach Manicotti

8 oz pkg sliced mushrooms
10 oz pkg frozen chopped spinach,
    thawed and drained
2 cloves garlic, minced
3 egg whites
15 oz container ricotta cheese
1 c shredded Mozzarella Cheese
1/3 c grated Parmesan Cheese
8 oz pkg manicotti shells (14 shells)
   cooked and drained
2 c spaghetti sauce

Preheat oven to 350 degrees. Spray a large frying pan with cooking spray. Saute mushrooms and garlic for 5 minutes on medium heat, stirring frequently; remove from heat. In a medium mixing bowl, beat egg whites until foamy and add mushrooms, spinach, ricotta cheese and half of the mozzarella and Parmesan cheeses; mix well. Spoon mixture evenly into manicotti shells. Place in a 13x9-inch baking dish sprayed with cooking spray. Cover with spaghetti sauce. Bake 40 minutes at 350 degrees. Top with remaining mozzarella and Parmesan cheeses and continue to bake for 5 more minutes or until cheese is melted. Makes 7 servings of 2 stuffed manicotti shells each.