Baked Spaghetti

1.Heat a large skillet over medium-high heat. Add the ground beef and onions and cook, stirring, until the beef is browned and broken up. Drain off any grease.
2.Cook spaghetti according to package directions; drain and set aside. Preheat oven to 350 degrees F.
3.Meanwhile, add the salt, pepper, chili powder, 1/4 cup of the cheddar, the Worcestershire sauce, ketchup, and mustard to the ground beef. Mix well and simmer for 5 minutes.
4.Stir in the beef stock then add the cooked pasta. Mix well. Spoon the mixture into a 3-quart sized baking dish. Top with the remaining cheddar and jack cheeses.
5.Bake at 350 degrees F for 20-30 minutes or until the cheese is browned and bubbly. Serve hot.