Preheat oven to 350 degrees.

Soften spaghetti squash by poking the squash all over with a knife and cook in the microwave for 12 minutes, until soft. Let cool for about 10 minutes before handling.

Spray a medium sized, non-stick skillet with cooking spray, and set over medium high heat.

Add in the zucchini, garlic, salt and pepper. Saute until zucchini becomes tender, about 5 minutes.

In a medium sized bowl, combine ricotta, parmesan, oregano and basil. Fold in the cooked zucchini.

Cut the squash in half, scoop out the seeds, and with a fork, scrape the flesh from the peel. It should flake off easily in strings, resembling spaghetti.

Place the spaghetti squash flesh in a casserole dish. Spoon the ricotta mixture and spread it evenly throughout the squash. Pour tomato sauce over everything.

Layer cheese slices evenly on top and bake for 30 minutes or until the cheese is bubbly.