Prep the vegetables: Dice the onion and bell pepper.
Brown the ground beef and vegetables: Cook the ground beef, onion, and bell pepper in a large skillet over medium-high heat until the beef is browned, about 5–7 minutes. Drain any excess grease if needed.
1 pound ground beef, 1 cup onion, 1 bell pepper
Add seasonings: Add the mustard, brown sugar, garlic, paprika, salt, and pepper, then stir to combine.
1½ tablespoons yellow mustard, 1½ tablespoons brown sugar, 2 teaspoons garlic, 2 teaspoons smoked paprika, ½ teaspoon salt, ¼ teaspoon black pepper
Add liquid and pasta: Stir in the beef broth, water, and ketchup, then add the pasta.
1 can beef broth, 1 cup ketchup, 2 cups pasta, ½ cup water
Cook: Bring to a boil, then reduce the heat to a simmer. Cover and cook, stirring occasionally, until the pasta is tender, about 13–15 minutes.
Top with cheese: When the pasta is tender, remove the skillet from the heat. Top with shredded cheese, cover, and let the cheese melt.
1 cup shredded cheese