Stuffed Shells

2 cups ricotta cheese
3 cups mozzarella cheese
1 8-oz pkg. chopped, frozen spinach
1 ½ cups parmesan cheese
1 pkg. large shell pasta
2 tsp. pepper
Favorite spaghetti sauce

Drain spinach. Mix cheeses, spinach & pepper together. Cook pasta shells according to instructions on box. Stuff each shell with cheese mixture. Place in a casserole dish and top with your favorite spaghetti sauce. Bake for 30 minutes at 350°.