1Line 15x10x1-inch pan with foil. Set oven control to broil. Cut bell peppers into quarters, removing membranes and seeds. Place skin sides up in pan; press down to flatten.
2Broil peppers with tops 4 to 6 inches from heat about 10 minutes or until blackened. Wrap foil around peppers; let stand 20 minutes. Remove skin from peppers; discard. Cut peppers into 1/2-inch pieces. Set aside.
3Meanwhile, in 4-quart saucepan, heat oil over medium-high heat. Cook onion and garlic in oil 2 to 3 minutes, stirring constantly, until crisp-tender.
4Stir in tomatoes, broth, sugar, red pepper flakes and salt. Heat to boiling. Reduce heat; simmer 15 minutes. Stir in roasted peppers; heat until hot.