Cook the soffritto: Warm the olive oil in a soup pot over medium heat, then cook the onion, carrot, and celery until softened, about 8 minutes.

Add the garlic: Stir in the garlic and cook for 30 seconds until fragrant.

Simmer the soup: Add the diced tomatoes, broth, beans, salt, and black pepper and simmer for 15 minutes so the flavors come together.

Cook the pasta: Stir in the ditalini and cook until tender, about 8 minutes, adding a splash of water if the soup tightens too much.

Adjust the broth: Taste the soup and add more salt or hot water if you want a looser, brothy finish.

Serve the bowls: Ladle the soup into bowls and top with parsley and Parmesan if using.