There are many strange versions of this classic sauce, so I’ll add my recipe into the fray.
1 1/3 c. Mayonnaise, of firm texture (see recipe here)
A Handful of Capers (extra-fine if possible)–well drained
A Handful of Cornichons*, chopped in a coarse dice (see recipe here)
2 Hard-Boiled Eggs, peeled, chopped (neither too fine nor too coarse)
3 Springs of Tarragon, leaves only, chopped
A Small Handful of Curly Parsley, chopped
Mix all the ingredients together and serve.
*Cornichons are simply small, whole pickles; like dilled gherkins.
This excerpt is taken from The Whole Beast by Fergus Henderson, purchase the book here.