Place the char with the skin up on a greased oven tray. Cover with cling film and smoke the fish with a smoking gun (or leave it unsmoked if you don’t have access to a smoker). Bake the fish in an oven at 90°C. The fish is done when the skin can be easily removed.
Peel the potatoes. Roast the peels in an oven at 200°C for 30 min. Boil the peeled potatoes in salted water and press them throygh a sieve. Boil the roasted peels in the milk and cream for 15 minutes. Strain the milk mixture and mix with the potatoes, butter and sour cream to a soup like consistency. Season with salt and fill in a siphon. Load with 3 gas cartridges. Keep warm until serving.
Mix the wet ingredients in one bowl and the dry ingredients in another bowl. Combine the two and mix well. Spread the batter onto a silicone sheet and place another one on top for extra weight. Bake for 20 mins in an oven at 150°C. Remove the top silicone sheet and bake another 5 mins. Allow to cool and break into pieces.
Split the pickling onions lengthwise and steam for 30 seconds. Peel them and place them in the liquid.
Peel the shallots and slice them thinly on a mandolin. Divide the slices into rings, toss in corn starch and deep fry until crispy.
Brown the butter and allow it to cool. Boil the potatoes just before serving and salt it lightly. Pluck the herbs and place them in cold water.