Start by heating a large skillet over medium-high heat. Add the lean ground beef and cook until it’s thoroughly browned, about 6–8 minutes. Drain excess fat and transfer the browned beef to your slow cooker.

In the slow cooker with the beef, add the chopped onion, red bell pepper, and minced garlic. Sprinkle in the Italian seasoning, salt, and black pepper. Pour in the bone broth alongside the crushed and petite diced tomatoes, stirring until fully combined.

Cover the slow cooker and set it to cook on HIGH for 2–3 hours or on LOW for 4–6 hours, or up to 8 hours for deeper flavors.

Cook the elbow macaroni according to package instructions separately, or add it to the slow cooker during the last 45 minutes of cooking.

Once cooking is complete, stir in the shredded cheddar cheese until melted. Mix in the cooked pasta if prepared separately, and serve hot.