Cook chopped onions and garlic in olive oil. Cut zucchini, green pepper, and tomatoes in small cubes and add to frying pan. Season with salt, pepper and garlic salt.
When veggies are tender, stuff into manicotti tubes.
Cover the bottom of a large frying pan with prepared tomato sauce. Add layer of spinach, sprinkle with Kraft Grated Parmesan Cheese. Lay stuffed manicotti on spinach. Drizzle the rest of the sauce over the tubes. Sprinkle the top with Kraft Grated Parmesan Cheese. Cover and leave on warm burner until ready to serve.