Thaw fish, if frozen. Rinse fish; pat dry with paper towels.
Preheat broiler. Lightly coat a 15x10-inch baking pan with cooking spray. Arrange tomatoes, onion, and garlic in pan; sprinkle with salt and crushed red pepper. Broil 3 to 4 inches from heat 10 minutes; gently stir in the tomato paste to coat the vegetables. Broil about 5 minutes more or until vegetables begin to blacken at the edges.
In a blender or food processor combine the tomato mixture and rosemary. Cover and blend until smooth. Transfer mixture to a saucepan; stir in the broth. Bring to boiling, stirring constantly; reduce heat. Simmer, uncovered,12 to 15 minutes or until reduced to 1 1/3 cups. Stir in heavy cream. Cover sauce and keep warm. If desired, drizzle with olive oil.
Lightly coat a broiler pan with cooking spray; place fish on pan. Brush both sides of fish with olive oil; season with black pepper. Broil 5 to 6 inches from the heat 8 to 12 minutes or until fish flakes easily, turning once. Serve fish with sauce and, if desired, snipped basil.