Preheat oven to 400 degrees. Line a baking sheet with aluminum 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 minutes, stirring occasionally.
Meanwhile, in a large bowl, combine beef, pork, onion, garlic, egg, 1/4 cup ketchup, 1 1/2 teaspoons salt, and 1/4 teaspoon pepper. Add bread-milk
mixture, and mix very gently with a fork (do not overmix).
Place meat mixture on prepared baking sheet, and form into a loaf about 9 inches long and 4 to 5 inches wide.
Bake, brushing twice with remaining 1/4 cup ketchup during baking, until an instant-read thermometer registers 160 degrees, 45 to 55 minutes. Let meatloaf rest 10 minutes before slicing and serving.