1. Cut each squash in half lengthwise. Scoop out seeds. Place squash halves, cut sides up, on a baking sheet. Bake at 350° for 50 minutes. Scrape inside of squash with a fork to remove spaghetti-like strands.
2. Heat a large skillet over medium-high heat. Add oil to pan. Add spinach; cook until spinach wilts. Remove from heat. Combine spinach mixture, squash strands, ricotta cheese, salt, and half of mozzarella cheese together and remove from skillet.
3. Return skillet to medium-high heat. Add turkey to pan; cook 4 minutes or until browned. Add sauce; cover, reduce heat to medium, and simmer 4 minutes.
4. Mix in spaghetti squash into skillet. Sprinkle evenly with remaining mozzarella cheese and Parmesan cheese. Cook until cheese is melted.