Bring the chicken stock to the boil.
Wash the carrots and the celery. Peel the carrots and use a mandoline to cut both vegetables into julienne strips. Wash the leeks and slice into 1cm rounds. Wash the spring onions, remove the root and separate the bulb from the stem. Finely slice the stem and set aside.
Add the carrots to the stock and cook for 2 mins. Add the celery and the spring onions, season with salt. Finally add the leeks. Once the vegetables are cooked, remove from the stock and place in a bowl of cold water, reserving the stock to one side. After a couple of minutes, remove from the water and drain.
Add the chicken supremes to the stock and cook for 15 minutes over a high heat. Remove from the stock and place on a baking tray. Season with fleur de sel and black pepper then set aside.
Reduce the stock by a fifth and then lower the heat. Add 250ml creme fraiche and 4 egg yolks, whisking vigorously. Add the grated nutmeg.
Return the chicken and the vegetables to the stock to warm through and then add the chopped spring onion stems.
Place the vegetables on to dinner plates and top with the chicken. Drizzle some sauce over the top and finish with chopped parsley.
«Make sure not to overcook your vegetables, this dish works well when they have a little crunch to them.»