Put the saffron threads in a small dry frying pan over a high heat and toast, stirring, for 1
minute, or until you can smell the aroma. Immediately tip out of the pan and set aside.
Melt the butter over a medium heat in a frying pan with a tight-fitting lid. Add the carrots,
celery, courgette, shallot, garlic, bouquet garni, salt and pepper. Saute for 3 minutes, without
letting the vegetables colour.
Meanwhile, bring the wine and water to the boil in a saucepan over a high heat, then boil for 2
minutes. Pour the boiling liquid over the vegetables, then reduce the heat to low and simmer for 5
minutes. Remove from the heat and discard the bouquet garni.
Place the fish over the vegetables in a single layer, then cover and simmer for 5 minutes, or
until the fish is cooked through and flakes easily. Remove the fish and vegetables to a warmed bowl
and spoon over a little of the poaching liquid. Cover with foil and set aside.
Stir the soured cream and saffron into the poaching liquid and bring to the boil, stirring. Boil
for 3-5 minutes to reduce. Place a mound of vegetables on each soup plate and top with the fish.
Spoon over the reduced liquid and garnish with the chervil.