In a medium bowl, mix together the remaining 1⁄4 cup of parsley, beef, pork, 1⁄4 cup of Parmesan cheese, basil, oregano, onion powder, garlic, salt, and pepper.
Form the mixture into 12 meatballs.
In a large skillet over medium-high heat, heat the remaining tablespoon of oil olive for about 1 minute. Add the meatballs. Brown for 1 to 2 minutes on each side until fully browned, about 5 minutes total.
Add the pasta sauce to the pan. Stir to coat the meatballs thoroughly.
Reduce the heat to low. Cover the skillet. Cook for 10 to 15 minutes, or until the meatballs are cooked through.
Plate 3 meatballs and 1⁄4 cup of sauce over one-quarter of the spaghetti squash per person. Sprinkle the remaining 1⁄4 cup of Parmesan cheese evenly over the plated servings.