In a small bowl combine ketchup, brown sugar, 1 tablespoon of the lemon juice, and mustard powder.
In a large bowl combine ground beef, bread, remaining lemon juice, onion, egg, seasoning and ⅓ of the ketchup mixture. Mix well and place in a loaf pan.
Bake for 1 hour, drain any fat off, then spread remaining ketchup mixture evenly over the top. Bake for 5-10 more minutes, then serve.
To prepare for freezer:
Prepare as raw meatloaf mixture as directed and form into a loaf.
Line a loaf pan with foil or freezer paper, then form the loaf to the pan.
Freeze loaf without cooking, reserving ⅔ of the ketchup mixture. Freeze the ketchup mixture in a small container that can be placed with the frozen meatloaf. When meatloaf is frozen, remove from the loaf pan using the foil or freezer paper as leverage. Wrap for the freezer with the extra glaze and label with: “Glazed Meatloaf: Thaw and bake for 1 hour at 350ºF. Drain fat and spread glaze over top of meatloaf. Bake 5-10 more minutes.”