In a nonstick pan, cook sausage over medium-high heat until browned, stirring occasionally. Drain fat, then reduce heat to medium.
Add onion, peppers and garlic; cook for about 10 minutes, or until vegetables are tender. Stir in diced tomatoes, tomato puree and 1/4 teaspoon salt; simmer on low for 10 minutes.
Meanwhile, bring a large pot of water to a boil with a dash of salt. Add pasta and cook until almost done. Drain pasta, return it to the pot, and stir in the sauce and mozzarella.
Transfer pasta mixture to a 9-by-13-inch baking dish and sprinkle with Romano cheese. Bake, uncovered, for 20 minutes, or until browned.
Let stand for 10 minutes before serving. Makes 8-10 servings.
Recipe Notes
*Brands may vary by region; substitute a similar product.