Shells Florentine

1 pkg (10 oz) chopped spinach, thawed and well drained
1 cup shredded mozzarella cheese
1 cup ricotta cheese
1 egg
1 tablespoon Parmesan cheese
1 teaspoon oregano
1/4 teaspoon ground pepper
1/4 teaspoon garlic powder
1 pkg jumbo shells, cooked (at least 16)
1 jar spaghetti sauce or the equivalent of homemade

1. Move oven rack to the lower middle position and preheat the oven to 375°.
2. Mix the spinach, mozzarella cheese, ricotta, egg, Parmesan cheese, oregano, pepper, and garlic powder together until well blended.
3. Fill each shell with a heaping spoonful of the spinach mixture. Please into a 12x9 in baking dish and cover with sauce.
4. Cover tightly with foil and back for 30 to 40 minutes.