From:
The Thorough Good Cook
Sauces: 41. Monglas
Mix till quite
smooth a small spoonful of
flour with
butter, and moisten with the
liquor in which you have boiled the
joint with which the
sauce is to be served. Add some
juice of
mushroom, and let it boil for ten minutes. Remove the
saucepan from the fire. Thicken with three yolks of eggs beaten up with
milk. Then bring it to the boil again, 'taking care to stir all the time. To be really good, this sauce should be
thick. Add the juice of a
lemon, some
truffles cut in shreds, the tails of
crayfish or a few
shrimps, and a little
parsley.