Put in a very clean stewpan the chervil, lettuces, onions, parsley, and butter, to 1 pint of water, and let them simmer till tender. Season with salt and pepper; when done, strain off the vegetables, and put two-thirds of the liquor they were boiled in to the stock. Beat up the yolks of the eggs with the other third, give it a toss over the fire, and at the moment of serving, add this, with the vegetables which you strained off, to the soup.
Time: 3/4 of an hour.
Seasonable from May to October.
Sufficient for 8 persons.