White Villeroy
Ingredients: Butter, flour, eggs, cream, nutmeg, white stock.
Make a light-coloured roux by frying two ounces of butter and two
ounces of flour, stir in some white stock and keep it very smooth.
Let it boil, and add the yolks of three eggs, mixed with two
tablespoonsful of cream and a pinch of nutmeg. Pass it through a
sieve and use for masking cutlets, fish, &c.
See also: Wikipedia Cookbook.
Source: The Cook's Decameron: A Study In Taste, Containing Over Two
Hundred Recipes For Italian Dishes from a project that puts
out-of-copyright texts into the public domain. This is from a *very*
old source, and reflects the cooking at the turn of the last century.
Update as necessary.