While the pasta is cooking, sauté onion, garlic, and green pepper in skillet until tender.
Combine tomatoes, mushrooms, and pizza sauce in bowl.
Add spaghetti, vegetables, and seasoning to bowl and stir to combine. Top with cheese and bacon.
Bake at 350°F for 30 minutes or until cheese is melted and casserole is heated through.
For a vegetarian version, omit the turkey bacon.This recipe freezes well, so it's a good dish to double or triple to stock your freezer. If freezing, I'd recommend slightly undercooking the pasta (just reduce cooking time by a minute or two). Wrap in freezer paper and/or foil and label with "Baked Spaghetti: Thaw, then cook for 30 minutes at 350ºF".