For the haddock, clean, acidify and salt the fish.
Clean and chop the greens.
Put all the ingredients in an unperforated cooking container and cook (at 100°C for 10-12 minutes).
Beat yolks with fish stock and white wine in a water bath until foamy. Add mustard and double cream and season with pepper, salt, sugar and white wine.
As a side dish, you can serve haddock with dill potatoes and cucumber salad as desired.
Preparation Tip:
You can also replace haddock with redfish. Mustard seeds are a European spice used mainly to prepare mustard (also called mustard), sauces, marinades and salads, but can also be eaten with sausage, fish and meat.