1 c. ricotta
1 c. shredded Mozzarella cheese
1/4 c. grated Parmesan
1 egg, slightly beaten
1 (10 oz.) pkg. frozen chopped spinach, cooked and well drained
1/2 tsp. dried oregano leaves, crushed
1/4 tsp. salt
12 jumbo shells, cooked, drained and cooled
1 (15 1/2 oz.) jar Prego spaghetti sauce

In bowl, mix well first seven ingredients. Stuff about 3 tablespoons cheese mixture into each shell. In 12 x 8 inch baking dish, spread 1/2 of the Prego sauce. Arrange shells, stuffed side up, in sauce. Spoon remaining sauce over shells. Cover with foil. Bake at 350 degrees for 35 minutes or until hot.