Brush the cut sides of the squash with the olive oil and place them cut-side down on a baking sheet.
Bake for 25 minutes, or until the squash is tender.
Meanwhile, in a large skillet over medium-high heat, heat the oil and sauté the onion until translucent, about 5 minutes. Add the garlic and cook for 1 minute.
Add the bacon, Italian seasoning, salt, and pepper and cook for another minute.
When the squash is done, remove it from the oven and turn the oven up to 400°F (204°C).
Using a fork, scrap the spaghetti squash out of the shells into a large bowl. Add the onion mixture, mozzarella cheese, and Parmesan cheese and mix until combined.
Divide the mixture evenly between the squash shells and place them back on the baking sheet. Bake for 15 minutes, or until the cheese is melted and lightly browned.
Serve hot.
Interesting Facts
Spaghetti squash is a great source of Vitamin A, folate, potassium, and fiber.
This dish can easily be made vegetarian by omitting the bacon.
It can also be made vegan by substituting vegan cheese for the mozzarella and Parmesan cheeses.