Ground beef, panko, parsley, allspice, nutmeg, onion, garlic powder, pepper, salt, and egg should all be placed in a medium-sized basin and mixed well.
Form into 20 little or 12 big meatballs. Heat one tablespoon of butter and olive oil in a big skillet. Add the meatballs and heat, rotating often, until cooked through and browned on both sides. Move to a plate, then tent with foil.
In a pan, combine 4 Tablespoons butter and flour; stir until browned. Add heavy cream and beef broth and stir slowly. When the sauce begins to thicken, add the dijon mustard and worchestershire sauce and boil. To taste, add salt and pepper.
Return the meatballs to the skillet, then cook them for one or two more minutes. Serve with rice or egg noodles.