In a bowl, combine breadcrumbs and milk. Let sit until breadcrumbs absorb the milk. Add ground beef, ground pork, and egg. In a separate bowl, mix the nutmeg, allspice, salt, garlic powder, and pepper. Add this spice mixture to the meatball mixture. Mix until just combined.
Shape the mixture into 1 1/2-inch meatballs.
Heat olive oil in a skillet over medium heat and brown meatballs. Once they have color, you can remove them and set aside; they will finish cooking later.
In the same skillet, melt butter. Stir in flour and cook for 2 minutes until thickened. Gradually whisk in beef broth and bring to a simmer. Stir in heavy cream, Worcestershire sauce, and a pinch of nutmeg. Season with salt and pepper to taste, and adjust the flavor as needed.
Return meatballs to the same skillet. Cover with a lid and simmer over low heat for 10 minutes, or until meatballs are cooked through. Garnish with fresh parsley, and serve hot.