In the container of a blender, pulse together tomatoes and roasted red peppers until smooth.
In a deep 12-inch cast-iron skillet, heat oil over medium-high heat. Reduce heat to medium. Add sausage and onion; cook until sausage is browned, about 10 minutes. Remove mixture from skillet.
Add rigatoni, 8 cups cold water, and 2 teaspoons salt to skillet; bring to a boil over medium-high heat, stirring frequently. Cook, stirring frequently, until almost tender, about 8 minutes. Drain.
Return pasta to skillet; stir in tomato mixture, sausage mixture, basil, oregano, garlic powder, crushed red pepper, and remaining ¾ teaspoon salt. Cook over medium-low heat, stirring frequently, until heated through, 5 to 7 minutes. Sprinkle with cheese. Garnish with basil and red pepper, if desired.
Recipe by Southern Cast Iron at https://southerncastiron.com/smoked-sausage-and-roasted-pepper-rigatoni/