Green Sauce for Ducklings or Green Geese.
Pick green spinach or sorrel, wash it, and bruise it in a marble mortar, and strain the liquor through a tamis cloth. To a gill of the juice add a little loaf sugar, the yolk of a raw egg, and a spoonful of vinegar; if spinach juice, then put one ounce of fresh butter, and whisk all together over a fire till it begins to boil.
N. B. Should the sauce be made of spinach juice instead of vinegar, there may be put two table spoonfuls of the pulp of gooseberries rubbed through a hair sieve.