Crockpot: Place meat and onions in a large non-stick sauté pan, and cook until meat is browned. Add onions and meat into the crockpot with the rest of the ingredients. Cook for 4 hours on high, or 8 hours on low.
If using pasta: When the crockpot has about 1 hour left, add the pasta and stir to combine. Place the lid back on the crockpot and continue to cook about 30-60 minutes, or until the pasta is cooked through. Enjoy with a sprinkle of parmesan cheese on top if desired!
Stovetop: Spray a large pot with cooking spray, and bring heat to medium-high heat. Add the turkey, onion, and garlic. Cook, breaking up the meat with spoon, until turkey is browned and onions are softened. Add zucchini, spinach, tomatoes, tomato sauce, and the rest of the seasonings. Bring tomato sauce to a boil. Reduce heat to medium-low and allow sauce to simmer for about 15 minutes.
If using pasta, add pasta to the pot during the last 10-15 minutes of cook time. Continue to allow sauce to simmer over medium heat until the pasta is cooked through, about 10-15 additional minutes. Enjoy with a sprinkle of parmesan cheese on top if desired!