In a large saucepan, heat oil over medium-high heat, then add shallot and cook 3 to 4 minutes or until tender. Stir in broth, tomatoes, zucchini, and beans. Bring to a boil. Reduce heat; simmer, uncovered, until zucchini is tender, about 10 minutes. Stir in vinegar.Advertisement
Serve with garlic-bread knots.