1. Heat olive oil in a large stockpot or Dutch oven over medium high heat. Add ground beef and onion and cook until beef has browned, about 3-5 minutes, making sure to crumble the beef as it cooks; season with salt and pepper, to taste. Drain excess fat.
2. Stir in tomatoes, tomato sauce, chicken broth, ketchup, mustard, pasta and 2 cups water. Bring to a boil; cover, reduce heat and simmer until pasta is cooked through, about 13-16 minutes.
3. Remove from heat and top with cheese. Cover until cheese has melted, about 2 minutes.
4. Serve immediately, garnished with tomato and green onions, if desired.

Recipe sources [1]