In a rectangular dish, mix 5 tablespoons of Régilait powdered milk with 75cl of water. Leave your cod fillets to soak in this mixture for 10 minutes.
Meanwhile, peel the carrot and the ginger. Cut them into small pieces. Finely chop the spring onion whites. Cut the fennel bulb into thin slices. Rinse the lemon. Cut half of it into slices and then cut these into four.
Place everything in a skillet and cover with a litre of cold water. Salt and pepper. Bring to a gentle boil.
Place the cod fillets in the stock and poach them at a low heat, without boiling so as not to break them.
Serve the cod fillets immediately in a soup dish with a ladle of stock. Sprinkle with finely chopped chives. Accompany with white rice.