In a small bowl, soak the breadcrumbs in the milk and set aside.
In a large mixing bowl, combine the ground beef, ground pork, finely chopped onion, soaked breadcrumbs, egg, ground allspice, ground white pepper, and salt.
Mix the ingredients thoroughly until well combined.
With damp hands, shape the mixture into small meatballs, about 1 inch in diameter.
In a large skillet, heat the butter over medium heat.
Add the meatballs in batches, making sure not to overcrowd the pan.
Fry the meatballs, turning them frequently, until they are browned on all sides and cooked through. This should take about 7-10 minutes per batch.
Remove the meatballs from the skillet and set aside.
In the same skillet, add the butter for the gravy and melt over medium heat.
Stir in the flour and cook for 1-2 minutes, stirring constantly, to make a roux.
Gradually add the beef broth, stirring constantly to avoid lumps.
Add the heavy cream and soy sauce, and continue to stir until the gravy thickens.
Season with salt and black pepper to taste.
Return the cooked meatballs to the skillet with the gravy.
Simmer for a few minutes until the meatballs are heated through and well coated with the gravy.
Enjoy your meal!