Combine the breadcrumbs and milk. Let them sit for a few minutes until the breadcrumbs absorb the milk. Add the ground beef, ground pork, soaked breadcrumbs, finely chopped onion, parsley, egg, salt, black pepper, allspice, and nutmeg.
Mix all the ingredients until well combined. Shape the mixture into meatballs. You should get about 24 meatballs.