Take off the outside layer of the leeks. Chop off all but 10cm of the dark green end (keep this portion for making leek and potato soup). Really wash them well. Trim the little beard from the end if there is any; do not completely chop off the soil end, as this helps to keep the leek together. If very long, chop each leek in half along the middle.
Get some salted water on to boil. Cook the leeks for long enough so that when the point of a knife is rested on them the weight of the knife naturally slides into the flesh. The leeks should offer no resistance to the blade; they must be soft to the cut and to the teeth. This should take about 7 minutes.
When ready, lift the leeks from the hot water into a colander sitting over a small pan. Do so carefully â€“ if you have cut them in half, as the greener part of the leek cooks, each inner layer when handled might have the tendency to slip from the centre like a telescope. Donâ€™t throw the water away.
Lay the leeks against the sides of the colander with the root ends uppermost rather than flat across its bottom, as this will allow the water to drain out.
Run a little cold water over them to cool them.
Using the leftover leek water, gently boil the eggs for 7 minutes until hard. When done, put them in a bowl of cold water to cool completely, as grating a warm egg is never particularly successful.
Turn your attention to the vinaigrette. Mix the mustard, lemon juice, vinegar, sugar and a pinch of salt in a bowl before slowly beating in the olive oil with a fork. It will emulsify into a creamy consistency. It is time to assemble the dish. In the centre of a plate â€“ I like a large white one â€“ stack the leeks in a triangle like a log-pile. Peel the eggs, separating the white from the yolk. Grate the white on the medium setting of the grater before grating the yolk in the same way. Lovingly spoon the vinaigrette over all the leeks before sprinkling over the egg yolk, parsley and egg white, in three separate coloured bands. Destroy the pile instantly with a fork.