Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).

Cut spaghetti squash in half lengthwise and scoop out the seeds. Place face-down on a rimmed baking sheet and add about three tablespoons of water directly on the sheet. Let roast for 30 minutes.

When ready, remove from oven and discard any extra water.

Meanwhile, dice all the vegetables finely.

In a large pan or shallow pot or wok, heat oil and add onions. Sauté until translucent, and then add remaining vegetables.

Cook over medium heat, stirring occasionally to make sure the vegetables cook evenly. Cook until veggies are softening, about 10 minutes. Add the basil and marinara sauce.

Scrape out the flesh of the baked spaghetti squash with a fork, and set aside the shells for later use. Place spaghetti flesh into the vegetable mixture and mix all together to coat. Add salt and pepper to taste. I like to add a touch of sugar to counter the acidity.

Place a few spoonfuls of the vegetable filling back into the scooped-out shells and sprinkle each one with a quarter cup of shredded cheese.

Return to baking sheet and place in oven again for about eight minutes or until cheese is beginning to brown. Serve and enjoy!