Cook the Pasta: Bring a large pot of salted water to a boil. Add rotini and cook according to package directions until al dente. Drain and set aside.

Make the Meat Sauce: In a large skillet over medium-high heat, cook the ground beef, diced bell pepper, onion, and garlic until the beef is no longer pink and the vegetables are tender—about 10 minutes. Drain excess grease if needed.

Stir in mustard, brown sugar, Worcestershire sauce, ketchup, tomato sauce, salt, and pepper. Let everything simmer together for 5 minutes to bring out all those rich, tangy Sloppy Joe flavors.

Add the cooked pasta and 1 cup of shredded cheddar cheese to the skillet. Stir until everything is well combined, then turn off the heat.

Serve: Sprinkle the remaining 1/2 cup cheese over the top. Cover and let sit for 5 minutes, until the cheese is melted and gooey. Serve warm and enjoy!