Ingredients

4 large mackerel, filleted
Curing mixture
1 tablespoon black peppercorns, crushed
2 tablespoons sea salt
1 tablespoon caster sugar
1 bunch dill, coarsely chopped
Sauce
2 tablespoons Dijon or German mustard 1 tablespoon sugar
1 large egg yolk
5 fl oz (150 ml) good-quality olive oil
1 tablespoon lemon juice or white wine vinegar
Freshly ground black pepper
1 tablespoon dill, finely chopped

Wash the mackerel fillets and pat dry with kitchen paper. Prepare the curing mixture. Crush the peppercorns using a pestle and mortar, or the back of a wooden spoon or rolling pin, and combine with the salt and sugar.

Place one fillet of each pair skin side down, rub in an eighth of the curing mixture, then cover with the chopped dill. Adjust the amount of dill to your preference, but use a generous amount to achieve the characteristic flavor of this recipe. Rub another eighth of the remaining curing mixture into the corresponding fillet of each pair and place it skin side up on its mate, forming 4 'sandwiches'. Lay these in a shallow glass or earthenware dish, scattering over any remaining dill.

Cover with aluminum foil, then search for a suitable plate or inverted lid with which to weigh down the mackerel - place on top a heavy stone or brick from your garden, or any heavy object you can lay your hands on.

Leave the fish for at least 36 hours, or up to 4 days, in a cool place or refrigerator, turning the fillets every 12 hours or so as they become compressed and the curing mixture permeates them.

For the sauce, beat together the mustard, sugar and egg yolk and add the oil. The sauce is easily made by hand, or you can use a food processor or liquidizer. When you have added the lemon juice or white wine vinegar, check the taste and add a grinding of pepper, if you like, before folding in the chopped dill.

To serve, scrape off nearly all the dill and curing mixture (the odd peppercorn and green of the dill forms an attractive fringe to the slices). Using a very sharp knife, cut paper-thin slices across the fillets. Serve the sauce in a separate dipping dish

Makes/Serves: Serves 4 to 6