Preheat your oven to 350. Wash squash and cut in half from top to bottom. Scoop out seeds with a large spoon. Place each half face down on a cookie sheet and cover the bottom of the pan with water, about 1/2 cup. Bake for 30-40 minutes or until you can easily slide a knife through. Allow to cool slightly.
Use two forks to gently pull the squash back from the skin, fluffing it a bit. Pour 1 cup of sauce into each half and mix with the squash. Fill each half with meatballs and top with marinara sauce. Put them face up on the cookie sheet and bake for another 5-10 minutes to be hot for serving.
In a large stock pot, heat the oil over medium heat. Roughly dice and onion and garlic, and add to the pan. Allow to cook, stirring occasionally, for about 3-4 minutes or until fragrant. Add all ingredients. Bring to a low boil and simmer uncovered 2-3 hours, stirring occasionally. Remove bay leaf. Blend the sauce in a blender until you reach desired consistency.
Preheat oven to 350. Finely mince the onion, garlic, and parsley. Add all ingredients to a large bowl. Using your hands, gently mix together until combined. Roll 1/4 cup portions between your hands to make golf ball sized meatballs. Place meatballs on a foil lined cookie sheet and bake for 20-25 minutes or until cooked through.