Preheat the oven to 350°F (175°C).

In a large skillet over medium heat, brown the ground beef and onion until the beef is no longer pink.

Drain excess fat and stir in garlic powder, salt, and black pepper.

Add the beef broth, diced tomatoes, and pasta to the skillet. Bring to a boil, then reduce heat and simmer for 10 minutes until pasta is tender.

Transfer the mixture to a greased casserole dish.

Sprinkle the shredded cheddar cheese evenly on top.

Bake in the preheated oven for 15-20 minutes, or until the cheese is melted and bubbly.

Let cool for a few minutes before serving.