In deep nonstick 12-inch skillet, cook sausage over medium-high heat 5 minutes or until browned on all sides, stirring occasionally.
Reduce heat to medium. Discard all but 2 tablespoons sausage fat. To sausage in skillet, add garlic, peppers, and onion, and cook, covered, 10 minutes or until vegetables are tender, stirring occasionally.
Stir in tomatoes with their puree, tomato puree, and salt; heat to boiling over medium heat, breaking up tomatoes with side of spoon. Reduce heat to low; cover and simmer 10 minutes.
Meanwhile, preheat oven to 400°F.
Heat large covered saucepot of salted water to boiling over high heat. Add pasta; cook 2 minutes less than cooking time recommended on label.
Drain pasta. Return pasta to pot; stir in sauce to coat. Add mozzarella; toss to combine.
Transfer pasta mixture to ungreased 13 x 9-inch glass or ceramic baking dish and spread evenly; sprinkle with Pecorino Romano.
Bake, uncovered, 20 to 25 minutes or until top browns and sauce is bubbling. Let stand 10 minutes for easier serving.
Makes 10 main-dish servings.