Remove the yolk of the egg and reserve for another use. Chop the white. Combine it with the cornichons, capers, and parsley and chop them very fine.
Mix with the pistachios.
Beat the mustard and wine together, then beat in the oil.
Combine with the finely chopped pickle mixture.
Season with salt.
Serve as a condiment with pates, boiled meats, chicken, fish or sausages.