Preheat oven to 400 degrees.
Cut spaghetti squash in half lengthwise, use a spoon to scoop out the seeds, and brush the cut sides with oil. Add salt and pepper, to taste. Place on a baking tray, cut sides down. Bake 30-35 minutes, or until tender.
Meanwhile, sauté onions and garlic in a deep skillet over medium heat. After 2-3 minutes, add the meat to the skillet, stirring frequently, until cooked throughout, about 10 minutes.
Add spaghetti sauce, stirring to combine. Reduce heat to a simmer, stirring occasionally.
Meanwhile, combine ricotta, egg, parmesan, mozzarella, oregano, basil, thyme, and oregano in a small bowl.
Remove the skillet with the meat sauce from heat.