Steam the potatoes, keeping them whole with their skins intact. When a knife cuts into them easily, remove from steamer and allow to cool completely, without a lid on. When cool, cut into smaller pieces if necessary, though it is best to use potatoes small enough to keep whole.

To cook the eggs... Place in a large saucepan and cover with an extra inch of cold water. Bring to the boil, then turn the heat off, cover with a tight fitting lid and leave for 15 - 17 minutes, depending on the size of your eggs. Drain off the water, then plunge eggs into cold water with a few ice cubes added. (cooling them like this stops the green discoloration).

Peel the onions, then slice in half, from the root end to the growth end. Then place cut side down onto a chopping board, and slice into the center of the onion, to make half moon shapes. Add a generous amount of olive oil into a large, heavy based saucepan, and place over a medium heat. Add the onions with a pinch of salt. Sautee over a low heat, stirring regularly until the onions begin to colour and stick to the base. Sprinkle with a little balsamic vinegar, and continue to cook for a further 10 minutes. (ensure the heat remains low to prevent them cooking too fast, it will take about 30 minutes all up.)

Peel the eggs, and then slice into halves. Sprinkle yolks with a tiny amount of salt and set aside. Slice the celery or fennel into small slices. Roughly chop the dill, then combine with the lemon juice and the remaining olive oil.

To assemble, place potatoes in a large bowl, and add the onions, dill, lemon juice, capers, celery/fennel and olive oil. Sprinkle with sea salt, then add the eggs and gently mix through.