Lucas Herrings

Ingredients

Equipment Needed

• •1-quart shallow nonreactive dish for soaking
• •Medium mixing bowl
• •Balloon whisk
• •Clean lint-free kitchen towels
• •Shallow oval hors-d'œuvre serving dish

Instructions

1. 1

   Begin the desalting

   Rinse the herring fillets briefly under cold running water, then lay them flat in a shallow nonreactive dish and cover them with 4 cups (960 ml / 960 g) of the cold water. Refrigerate for 1 hour. Taste a small flake near the thick end after 45 minutes; it should be distinctly salty but no longer harsh. If the cure still catches at the back of your throat, replace the water and soak for another 30 minutes. Ça se rattrape. Don't chase away every trace of salt, because herring without its cure has lost its backbone.

   Cures vary enormously. The clock guides you, but the taste decides; this is why the first soaking cannot be reduced to a fixed professional-kitchen timetable.
2. 2

   Finish in milk

   Drain the herring and return it to the cleaned dish. Pour over the whole milk, turning the fillets so every surface is covered, and refrigerate for exactly 1 hour. The milk draws out the remaining aggressive salt while softening the cure's aroma. Drain and discard the milk, then press the fillets thoroughly between clean kitchen towels. If they still feel slick with moisture, leave them on fresh towels for 10 minutes. Wet fish thins the sauce and keeps it from holding; drying restores the proper surface.

3. 3

   Chop the finish

   While the herring finishes soaking, mince the shallot as finely as you can without turning it to paste. Chop the chervil and gherkin separately, measuring 1 teaspoon of each so together they equal the source entry's single dessertspoon. Keep them ready beside the bowl. Their pieces should be small enough to travel with the sauce rather than fall away from the fillets.

4. 4

   Build the mayonnaise

   Set a medium bowl on a folded towel so it cannot wander. Whisk the pasteurized yolks with the Dijon mustard, salt, and black pepper until smooth and slightly thickened. Add the neutral oil drop by drop for the first tablespoon, whisking constantly, then continue in a slender thread once the emulsion turns glossy and holds the trace of the whisk. Don't increase the oil to make an ordinary stiff mayonnaise. The source's yolk-rich, lightly oiled proportion gives a softer sauce that coats cured fish without burying it.

5. 5

   Sharpen and rescue

   Whisk in the white wine vinegar gradually, one tablespoon at a time. The mayonnaise will loosen into a sharp coating sauce, which is exactly right. If it separates, stop pouring: whisk the reserved 1 teaspoon (5 ml / 5 g) cold water in a clean bowl, then add the broken sauce a teaspoon at a time until the emulsion gathers again. Ça se rattrape. Fold in the shallot, chervil, gherkin, and cayenne, then taste. The sauce should be mustard-forward and brighter than a table mayonnaise, because the herring will absorb its edge.

6. 6

   Dress and rest

   Lay the dried fillets in a shallow hors-d'œuvre dish. Pour over the sauce, turning each fillet until completely coated, then nestle them in a single layer and spoon the remaining sauce across the top. Serve at once, as the source directs, or cover and refrigerate for 30 minutes to 4 hours for an easier dinner-party service. Take the dish from the cold 10 minutes before serving so the oil loses its chill and the mustard opens. À table!

Chef Tips

• •Buy true salt-cured herring sold ready to eat after desalting, not fillets already pickled in sweet vinegar or packed as a prepared salad. Pickling has done a different job, and another soaking cannot undo it.
• •Use a quiet neutral oil such as grapeseed or sunflower. A strongly flavoured olive oil turns the sauce toward another French larder and overwhelms the chervil; the book asks the emulsion to carry mustard, vinegar, and herring.
• •Fresh chervil has a soft aniseed fragrance that dried chervil rarely keeps. If fresh is unavailable, frozen chervil picked at its peak is the honest preserved choice. Parsley will make a pleasant sauce, but it will no longer be the Lucas dressing set down in the entry.
• •Pasteurized yolks are the sensible home equivalent for an uncooked sauce served to guests. Keep the finished dish refrigerated and use it within 24 hours.
• •Serve the fillets as a first course with good bread and a dry, brisk white wine. Keep the plate simple; the silver fish, ochre mustard sauce, green chervil, and diced gherkin already provide everything it needs.

Advance Preparation

• •The water and milk soaks can be completed earlier on the day of serving. Dry the fillets carefully, cover them, and refrigerate for up to 8 hours before dressing.
• •The complete dish is at its best after 30 minutes to 4 hours in the cold, which makes it well suited to a dinner party. With pasteurized yolks and steady refrigeration, leftovers may be kept for up to 24 hours.
• •Do not freeze the finished dish. Freezing damages the herring's firm texture and breaks the yolk-and-oil emulsion when thawed.

Frequently Asked Questions

Nutrition Information

1 serving (about 120g)