Sandre au beurre blanc

Method

1. 1 Cut the butter into small cubes and refrigerate them; the butter must be very cold when added to the sauce.
2. 2 Simmer chopped shallots with red vinegar and white wine until almost all the liquid has evaporated, leaving only 2 tablespoons of thick sauce.
3. 3 Add the heavy cream, then add the cold butter chunks one by one and beat continuously over the lowest heat.
4. 4 The butter must be cold and the heat very low; if it's too hot, the sauce will separate into a yellow oil and it will be beyond saving.
5. 5 Steam the catfish fillet for 8 minutes. Catfish is softer than dogfish, so steam it for a shorter time and don't stir it.
6. 6 Pour the white butter sauce over the fish, then squeeze in some lemon juice and sprinkle with parsley. Serve with boiled potatoes.

With an appliance

• Microwave 37 min

  Replace step 5: loosely cover the fish fillet plate and cook at 600 W for 6 minutes, then rest for 2 minutes to allow the fish to cook through; the white butter sauce from steps 1–4 remains on the stovetop.