In a Dutch oven cook onion, carrots, and garlic in hot oil over medium heat for 3 minutes, stirring occasionally. Add broth and the water. Bring to boiling. Stir in tortellini, meatballs, and Italian seasoning. Return to boiling; reduce heat. Simmer, uncovered, for 4 minutes.
Stir in spinach, roasted pepper, and, if desired, lemon juice. Simmer, uncovered, about 3 minutes more or until tortellini are tender. Season to taste with salt and black pepper. Before serving, stir in basil.