Make the sauce: Once the meatballs are transferred out of the pot, add the onions and garlic (without wiping the pot). Saute the onions and garlic, making sure to scrape the meat bits in the bottom of the pan from the meatballs, until the onions and garlic are translucent and lightly browned, about 10 minutes. Gently add the pureed and crushed tomatoes, water, salt, pepper, sugar, parsley and basil. Stir well and simmer the mixture uncovered over medium-low heat for 20 to 30 minutes, stirring often, or until the sauce starts to reduce. Gently place the meatballs into the tomato sauce and continue cooking uncovered, stirring occasionally, on a gentle simmer over low heat for 40 to 50 minutes until the sauce has thickened and the meatballs are cooked through and tender.