Preheat oven to 450. Cut your spaghetti sauce in half; scrap out seeds with a spoon
Brush on olive oil, sprinkle salt and pepper. Place on a tin-foil line baking sheet and set in the oven for 30 minutes.
When the spaghetti squash is done, use a paper towel to absorb any moisture/oil left inside the squash, then use a fork to shred the inside of the squash. This will make the "noodles".
Add in marinara, top with mozzarella cheese and set back in the oven for about 5 minutes, until the cheese is melted. Let it cool for 5 minutes, and enjoy!