Leg of Lamb with Puree of Onions with Cream

Cut off the end of the shank bone of a leg of lamb; pare the leg to shape and remove the superfluous fat; roast it on the spit or else in a baking pan in a moderate oven, pouring over some melted fat, and basting it frequently; salt it over fifteen minutes before serving. Dress and trim the handle bone with a paper frill (No. 10), and serve separately a puree of onions with cream prepared as follows: Mince two pounds of white onions, plunge them into boiling, salted water and let cook for five minutes, then drain very dry, and place them in a saucepan with four ounces of butter; cook the onions colorless, season and stir in two tablespoonfuls of flour; wet with cream in such a manner as to keep the mixture consistent, then set it into a slack oven, and when the onions have finished cooking, rub them through a sieve. Pour the puree back into the saucepan, mix well, heat and serve.