Cut the fennel and the onions into smaller pieces and sauté everything in a pan with a little oil on medium heat – the vegetables should not brown. Pour in the wine, stock and water and simmer for about 20 minutes, reducing somewhat. Pick the nettles off the stems and rinse under cold water. Chop the spinach and herbs roughly. Dice the cucumber. Mix the velouté base with the spring herbs and butter just before serving and finally add champagne, lemon and salt.
Spread the chicken skins out on a baking tray lined with a silipat mat or baking paper and roast in the oven at 200°C for 20 minutes or until crisp and golden. Save the chicken fat from the tray. Chop the crispy skin into smaller pieces. Shred the mushrooms by hand into strips (reasonably small). Pick the nettle leaves. Fry the mushrooms in oil and chicken fat until golden brown, add the chopped chicken skin and the nettles.
Bake the white onion whole at 200°C for about 30 minutes. Quarter the onions and sear the cut edges on the onion with a gas burner. Pick the layers apart and place the onions in a vacuum bag with the pickling liquid and seal. Pick the lovage in cold water and set aside until serving. Slice the celery thinly on a mandolin and rinse in cold water. Mix the cream and vinegar and put in the fridge.
If you do not have a vaccuum machine, place the onions in a plastic bag with the pickling liquid and seal to infuse.
When serving; arrange all the”dry” ingredients at the centre of the plates and pour the soup at the table. Drizzle a little of the vinegar/cream into the soup (do not use too much)!