Bring a saucepan of water to the boil, add the eggs, and cook for 9 minutes.
Drain then plunge eggs into cold water to cool. Crack and peel. Chop up roughly, place into a bowl along with the mayonnaise, yogurt, mustard, and curry powder
Mash with a fork until fine like scrambled eggs.
Add parsley and season.
Split the rolls, in half, add torn cos leaves add lashings of the curried egg mix.