The amount of capers and cornichons in this recipe are what I consider to be the minimum amount you want to add to the yoghurt. As I never really measure these ingredients, I sometimes end up with more than specified. Use more if you wish. However only add the amount of parsley specified below as it will overpower the other flavours. I only make this in small quantities, enough for one meal, so I have no idea if it will keep at all.