Heat oven to 375 degrees F. In a large bowl, combine ground pork, onion flakes, corn flakes, salt, pepper and egg. In a small bowl stir together ketchup, brown sugar and dry mustard. Spoon 2 tablespoons of the ketchup mixture into the pork and mix well. Spray muffin tin with vegetable cooking spray. Form 6 meatballs and place in muffin tin. Coat the top of each meatball with the remaining ketchup mixture. Bake for 30 minutes at 375 degrees F., until nicely glazed and internal temperature is 160 degrees F.