In a large bowl, combine the ketchup, brown sugar and mustard and mix well. Remove 4 tablespoons of this mixture and reserve for later for the top of the loaves. To the mixture in the bowl, add the Worcestershire sauce, salt, onion, garlic, egg, milk and ground black pepper and mix together well.
Stir in the wheat cereal squares and let stand for 5 minutes. Then break up the cereal squares and add the ground beef, mixing well. Shape the mixture into the mini loaf pans you've decided to use.
Bake at 350 degrees F (175 degrees C) for 65 minutes. Brush on reserved ketchup mixture and bake for 15 more minutes.