I found this recipe in a recent Southern Celebrations Autumn magazine (which, by the way, has a lot of great recipes in it as well as fall decorating inspiration…worth picking up), I altered the recipe a bit knowing a few of my guests object to both green peppers and mushrooms. It was still very tasty and a hit with everyone.
To prepare the meatballs, preheat oven to 375°. Line a rimmed baking sheet with foil. Place a wire rack over pan, and spray with cooking spray. In a large bowl, combine beef, sausage, egg, bread crumbs, grated onion, Parmesan, 1/2 teaspoon salt, pepper, and garlic powder. Shape mixture into 2” balls. Place on prepared rack. Bake for 10 minutes.
To make the sauce, in a large Dutch oven, heat oil over medium heat. Add diced onion and bell pepper; cook, stirring frequently until slightly tender, 5 to 6 minutes. Add mushrooms and garlic; cook for 2-3 minutes, stirring constantly. Add marinara sauce and remaining 1/2 teaspoon salt, stirring to combine. Add cooked pasta, 1-1/2 cups Monterey Jack, and 1/2 mozzarella, stirring to combine. Spray a 3-quart baking dish with cooking spray. Top with meatballs, remaining 1/2 cup Monterey Jack and remaining 1/2 cup mozzarella. Cover with foil.
Bake at 350° for 20 minutes. Uncover and bake until cheese is melted. Baking time might vary if made in advance and refrigerated.