In a mixing bowl, combine the ground turkey, onion, egg whites, parmesan, Panko, and garlic. Mix well and form into 1 inch balls.
In a large skillet with high sides, heat the olive oil. Once hot, add the meatballs and cook for 8 to 10 minutes on medium-high heat. Turn once or twice while cooking. Drain off any excess liquid.
For the Spaghetti
Add the diced tomatoes, marinara, water, and spaghetti to the same pan as the meatballs. Bring to a boil, cover, and simmer for 10 to 12 minutes until the pasta is tender. Additional water can be added if needed. Serve and enjoy!
If desired, additional grated parmesan or chopped parsley can be served on top!