Pappa al Pomodoro

Finely chop onion and mince garlic. In a 4-quart heavy kettle heat oil over moderately high heat until hot but not smoking and sauté onion and garlic, stirring, until softened. Drain tomatoes, reserving juice, and chop. Stir tomatoes and reserved juice into onion mixture and simmer, stirring occasionally, 15 minutes. While tomato mixture is simmering, discard crust from bread and cut enough bread into 1-inch cubes to measure 2 cups. Add bread and broth to tomato mixture and simmer, stirring occasionally, until bread has absorbed liquid and soup is thick, about 40 minutes. Season soup with salt and pepper.