In a large meat-safe bowl, add the ground beef and pork and mix until well combined.
In a small fry pan, add the butter and warm on medium heat. Once melted, add the onion, garlic, allspice, salt, white pepper and cook, stirring, until soft, ~5mins.
Add the milk and Worcestershire sauce and simmer for ~2mins and turn off the heat.
In a medium mixing bowl, add the breadcrumbs and combine with the milk mixture and allow to cool.
Once cooled, combine with the ground beef and pork, egg and egg white.
Mix until well combined
Form into 1inch meatballs and add to a lined or greased baking sheet. Place in the refrigerator for at least 1hrs, ideally 3-4hrs.
When ready, bake the meatballs in a 400 degree oven for 20 minutes.