1. Cook the beef: Start by browning the ground beef over medium heat. Break it up with your spoon or spatula as it cooks. Once it’s browned, drain any excess grease to keep the dish from being too oily.
   Tip: If you want to save time, you can start chopping your onion while the beef cooks.
2. Add aromatics: Toss in the finely diced onion and minced garlic. Stir everything together and let them cook for 2-3 minutes. The onion should soften, and your kitchen will start smelling incredible.
3. Add liquids and pasta: Pour in the beef broth, milk, and the undrained diced tomatoes. Stir to combine, then add the uncooked pasta. Make sure the pasta is submerged in the liquid—it’s the secret to evenly cooked pasta! Bring everything to a gentle simmer.
4. Cook the pasta: Reduce the heat to low, cover the pot, and let the pasta cook for 10-12 minutes. Stir occasionally to keep the pasta from sticking to the bottom.
5. Add cheese and seasonings: Once the pasta is tender, stir in the shredded cheddar cheese, Worcestershire sauce, and mustard. Keep stirring until the cheese is melted and the sauce is creamy. Season with salt and pepper to taste.
6. Serve and garnish: Ladle the pasta into bowls, sprinkle with fresh parsley (optional), and serve it hot.

Note: If the sauce feels too thick, add a splash of milk or broth to loosen it up.