Cook elbow macaroni according to package instructions; drain and set aside.
In a large skillet, brown the ground beef over medium heat, breaking it apart as it cooks.
Add diced onion and minced garlic; sauté until onion is translucent.
Stir in ketchup and mustard, mixing well.
Pour in beef broth and milk; bring to a simmer.
Add cooked macaroni to the skillet, stirring to combine.
Gradually add shredded cheddar cheese, stirring until melted and creamy.
Season with salt and pepper to taste.
Let it cook for an additional 2-3 minutes on low heat.
Serve hot, garnished with extra cheese or parsley if desired.