Prepare a mirepoix by mixing two ounces of butter, trimmings of lean veal and ham, a carrot, a shallot, a little celery, all cut into dice, a bay leaf, two cloves, four peppercorns, and a little thyme. 

Put this on a moderate fire so as not to let it colour, and when all the moisture is absorbed add a tablespoonful of potato flour. 

Mix well, and gradually add equal quantities of cream and fowl stock, and stir till it boils. Then let it simmer gently.

Stir occasionally, and if it gets too thick, add more cream and white stock. 

After two hours pass it twice slowly through a tamis to get the sauce very smooth.