1. Preheat oven to 400 F. Line a baking sheet with alum. foil or parchment paper. Place bread in food processor; pulse until fine crumbs form. Transfer to a small bowl; stir in milk. Set aside, about 10 mins., stirring occasionally.
2. Meanwhile, in a large bowl, combine beef, pork, onion, garlic, egg, 1/4 cup ketchup, 1 1/2 tsp salt, and 1/4 tsp pepper. Add bread-milk mixture, and mix very gently with a fork (do not overmix).
3. Place mixture on prepared baking sheet, and form into a loaf about 9 in x 4 to 5 in. wide.
4. Bake, brushing twice with remaining 1/4 cup ketchup during baking, until an instant-read thermometer registers 160 F., 45 to 55 mins. Let meatloaf rest 10 mins before slicing and serving.