In a medium-size mixing bowl, stir together ground beef, ground pork, bread crumbs, Worcestershire sauce, egg, 1/2 tsp allspice, 1/2 tsp nutmeg, 1/2 tsp salt, and 1/2 tsp pepper. Form into 1-inch meatballs.
Heat 1 tablespoon olive oil in a large skillet over medium-high heat. Working in batches, fry the meatballs in the oil until browned on all sides and cooked through. Be sure not to crowd the pan. Remove cooked meatballs from pan and set aside, draining any excess grease.
Make the gravy by melting butter in the same skillet used to cook the meatballs. Once butter is melted, stir in flour, nutmeg, and allspice until it forms a paste.
Slowly pour in beef broth and 2 tablespoons Worcestershire sauce (if using for added flavor) and heat over medium-high heat until thickened. Season with salt and pepper to taste. Stir in sour cream until combined.
Return cooked meatballs to skillet and stir with gravy to coat. Serve hot over mashed potatoes or cooked egg noodles. Garnish with chopped parsley if desired.
Instead of cooking the meatballs in the skillet, you can also bake these in an oven. Simply place shaped meatballs onto a lightly greased baking sheet. Bake in a 400 degree oven for approximately 30 minutes.