Preparation - In small bowl, mix the bread crumbs with 1/4 cup milk. Stir with a fork. Let stand at room temperature for 5 minutes. Place the ground beef in a large bowl. Add the egg, diced onion, salt, pepper, allspice and soaked bread crumbs. Mix together thoroughly. Shape into about 30 small meatballs. In a large skillet, melt the margarine over medium heat. Add the meatballs, about 15 at a time and saute' for about 10 minutes or until all the meatballs are browned on all sides and cooked through. Place the meatballs in a bowl and set aside. Add the flour to the pan drippings and stir until smooth. Add the bouillon cube and 3/4 cup boiling water. Bring the mixture to a boil over medium high heat, stirring constantly. Stir until the boullion is dissolved and the mixture is smooth. Add the half and half and the remaining 1/2 cup milk. Over medium heat - bring to a very low boil, stirring constantly. Reduce heat to low and cook for about 3 more minutes or until the sauce is thick and smooth. Return the meatballs to the skillet. Toss gently into the sauce. Serve immediately or transfer to a crockpot set on low to serve at a party or buffet.