Boil water for the pasta and cook it al dente according to package directions.

In a skillet, sauté the onion in the olive oil for 5 minutes over medium heat.

Add the ground beef to the pan and cook until browned, breaking it up with a spoon (about 5 minutes). Spoon out excess fat if necessary.

Stir in the garlic and chili powder, then add the tomato sauce and beef broth. Cook for 4-5 minutes, reducing the heat to a gentle simmer.

Stir in the heavy cream and season with salt and pepper as needed. Toss with the drained pasta shells and serve immediately.