Johnny Marzetti bakes ground beef, noodles, and tomato sauce with melted cheese for an Ohio family potluck legend. This protein-rich, budget-friendly casserole has been a Midwestern staple since the 1920s.
Preheat your oven to 350°F. Bring a large pot of salted water to a boil and cook the macaroni just until barely al dente, about 6–7 minutes; drain and set aside.
In a large skillet over medium-high heat, brown the ground beef, breaking it up with a spoon. Once fully browned (about 7–8 minutes), drain excess fat for a lighter casserole.
Add chopped onion and green bell pepper to the skillet with the beef. Sauté on medium heat for 5 minutes, until vegetables are softened and fragrant. Stir in minced garlic and cook for 1 minute longer.
Add tomato sauce, diced tomatoes, dried oregano, salt, and black pepper to the skillet. Simmer sauce on medium-low for 10 minutes, stirring occasionally, to develop flavor and slightly thicken.
In a large mixing bowl, combine the partially cooked macaroni with the meat sauce. Transfer mixture into a greased 9x13-inch baking dish. Top evenly with shredded cheddar cheese.
Bake, uncovered, in the preheated oven for 25–30 minutes, until the cheese is melted and bubbly with golden edges. Let rest 10 minutes before serving to set the casserole.