Preheat your oven to 350°F (175°C).
In a large skillet, brown the ground beef over medium heat until it's no longer pink, about 5-7 minutes. Drain excess fat.
Add diced onions and minced garlic to the skillet, and sauté for another 3-4 minutes until the onions are translucent.
Stir in the beef broth, diced tomatoes, pasta, mustard, and season with salt and pepper. Mix well.
Pour the mixture into a greased baking dish and cover with foil. Bake for 30 minutes.
Remove the foil, sprinkle shredded cheddar cheese on top, and bake uncovered for another 10-15 minutes until cheese is melted and bubbly.
Let it cool for a few minutes before serving. Optional: garnish with pickles and chopped fresh herbs, if desired.