Halve cherry tomatoes; dice onion and mince garlic.
In a large pot, combine the onion, garlic, water, pasta, crushed tomatoes, cherry tomatoes, basil, salt, and pepper. Stir to combine.
Bring to a boil over medium-high heat, then reduce to a simmer and cook uncovered until the pasta has softened, 25 to 30 minutes. Add the grated mozzarella and Parmesan, stir to combine.
Serve drizzled with balsamic vinegar. If desired, garnish with chopped basil and Parmesan. Serve with cubed honeydew.