Cut a deep pocket into the fat side of each pork chop, being careful not to cut all the way through. Combine bread crumbs, sugar, ground black pepper, salt, 3 tablespoons melted butter, onion, and parsley in a bowl until well mixed. Fill pork chop pockets with bread crumb mixture; secure with toothpicks.

Heat remaining 2 tablespoons melted butter in a skillet over medium heat. Cook pork chops until browned, about 5 minutes per side.

Add beef broth. Reduce heat to low and simmer, turning pork chops at least once, until tender and an instant-read thermometer inserted into the center of a chop reads at least 145 degrees F (63 degrees C), about 30 minutes.

Let pork chops rest briefly. Remove toothpicks and spoon pan juices over pork chops before serving.