Rinse the meat quickly with hot water. Place in a roaster and cover with the boiling water. Let come to a boil. Skim. Add the bay leaf, dill, salt and pepper. Simmer covered on top of the stove for 1½ hours. Remove lamb and reserve 2 cups of the stock.
Cut the lamb into small serving pieces and place on a hot serving platter. Serve with the following sauce: DILL SAUCE Melt the butter in a skillet, add the flour and stir continuously until smooth. Add the stock gradually, stirring after each addition. Add the rest of the ingredients alternately, beating a little after each addition. When mixture is smooth, remove from the flame and serve over the lamb. Garnish the platter with sprigs of parsley.