Pare the cucumber, quarter it, and take out the seeds; cut it in thin slices, put these on a plate with a little salt, to draw the water from them; drain, and put them in your stewpan, with the butter. When they are warmed through, without being browned, pour the stock on them. Add the sorrel, chervil, and seasoning, and boil for 40 minutes. Mix the well-beaten yolks of the eggs with the cream, which add at the moment of serving.
Time: 1 hour.
Seasonable from June to September.
Sufficient for 4 persons.