Preheat oven to 375 degrees. 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 until nicely glazed and internal temperature is 160 degrees.