Well pound two good handfuls of spinach in a mortar, and put it into a
thick cloth over a dish, twist up the cloth as tight as possible, until
you have extracted all the liquor, which put into a stewpan, and place
over the fire, the moment it boils it will curdle, when pour it upon the
back of a silk sieve, when cold take a spoonful of the green from off
the sieve, which put into a basin with a good spoonful of chopped
tarragon; have ready a good mayonnaise à la gelée (No. 1361), which put
into the basin, mixing the whole lightly, but well together; it will be
of a fine pistachio green colour, and is then ready for use where
required. To make it red, use the spawn of lobster and omit the spinach.
It requires to be extremely well seasoned.