In a large skillet with a lid or a Dutch oven, cook the ground beef, onion, and garlic over medium-high heat until no pink remains. Drain any fat.
Add the marinara sauce, broth, diced tomatoes with juices, tomato paste, bell pepper (if using), Italian seasoning, & bay leaves. Bring to a boil over medium-high heat.
Add the elbow macaroni, reduce the heat to medium-low, cover, and simmer for 10 minutes, stirring occasionally.
Uncover and simmer for an additional 5 to 10 minutes or until the pasta is tender.
Remove & discard the bay leaf. Top with cheese if using, and replace the lid. Let rest for about 5 minutes or until the pasta has thickened and the cheese is melted.
