Preheat oven to 400 degrees Fahrenheit. In the bowl of a food processor, pulse bread until fine crumbs form. Transfer to a medium bowl; add ground beef and ground pork.Place onion, garlic, celery, carrots and parsley in food processor; pulse until finely chopped. Add to beef mixture; combine using your hands. Add egg, 1/2 cup ketchup, 2 teaspoons dry mustard, salt and pepper; combine thoroughly, using your hands. Place in an 8 1/2-by-4 1/2-by-2 1/2-inch loaf pan.In a small bowl, combine the remaining 1/4 cup ketchup and 2 teaspoons dry mustard, and the brown sugar; stir until smooth.Brush mixture over top of the meatloaf. Place the pan on a baking sheet to catch drippings, and transfer to oven. Bake until a meat thermometer inserted in the center reaches 160 degrees, about 1 1/2 hours. (If the top of the meatloaf gets too dark, cover with foil and continue baking.) Let meatloaf stand 15 minutes before slicing.