Cut spaghetti squash in half, drizzle with olive oil, salt, and pepper. Place on tinfoil covered baking sheet, face down. Roast at x degrees for x minutes. Scoop out cooled squash and store.
Brown meat with 1/2 onion and garlic. Slice mushrooms and add. Add tomato sauce and Italian seasonings. Store.
Reheat and serve with meat sauce on top of spaghetti squash.