Preheat oven to 350°F (175 degrees C).

In a large bowl, combine the beef, egg, onion, milk and bread OR cracker crumbs. Season with salt and pepper to taste

Place in a lightly greased 5x9 inch loaf pan, or form into a loaf and place in a lightly greased 9x13 inch baking dish.

In a separate small bowl, combine the brown sugar, mustard and ketchup. Mix well and pour over the meatloaf.

Bake at 350°F (175 degrees C) for 1 hour.