Preheat oven to 400 degrees. Spray 1 medium and 1 large baking sheet with nonstick cooking spray.
Rinse the outside of the spaghetti squash. Cut in half lengthwise with a large knife. Scoop out the seeds and discard. Rub olive oil, salt, and pepper on the inside of the squash and place cut side down on the medium-sized baking sheet. Place in the oven and cook for 35-40 minutes, until the inside is tender when pierced with a fork.
While the squash is cooking, mix together the ground turkey, onion, garlic, breadcrumbs, grated parmesan cheese, egg, paprika, Italian seasoning, salt, and pepper in a medium bowl.
Form golf ball-sized meatballs and place them on the large baking sheet. Place in the oven and cook for 30 minutes, flipping meatballs halfway through.
In a medium-sized saucepan over medium heat add the pasta sauce and cook on low with a top on for about 10 minutes, stirring every couple of minutes. Turn the heat off once the sauce is hot.
Add the cooked meatballs into the sauce and mix until they are all covered.
Once the spaghetti squash is tender, using 2 forks, shred the inside of the spaghetti squash so that it looks like spaghetti.
Add the sauce and meatballs on top of the shredded squash along with the shredded parmesan cheese. Place back in the oven for 5 minutes, until the cheese is melted.
You can eat this directly out of the spaghetti squash or portion into bowls and enjoy!