Remove all the pin bones from the salmon. Spread a third of the dill in the bottom of a dish. Mix the salt, sugar and pepper, and sprinkle a third of it over the dill. Place one of the salmon fillets on top, skin-side down. Sprinkle half the remaining seasoning over the fillet, and lay half the remaining dill on top. Sprinkle on the cognac, if using it. Place the other fillet on top, sprinkle with the rest of the seasoning, and put the rest of the dill on top. Cover with foil, and weigh down. Refrigerate and keep for up to four or five days, though the salmon is good to eat after just 12 hours or so. To serve, wipe the dill and seasoning off the salmon, and cut into oblique or vertical slices. A sweet mustard mayonnaise is the traditional accompaniment (see below).
Break down the egg yolks, and mash until smooth. Stir in the mustard and sugar until there are no lumps. Gradually add the oil, a drop at a time, until the mixture begins to thicken. The oil can then be added in larger quantities. Add the vinegar, a splash at a time, in between additions of oil. Finally, season to taste with salt and pepper. A little chopped dill can be stirred in if you wish.
Omit the dill, and add a few crushed cardamom pods, cumin seeds and coriander seeds to the mixture of salt, sugar and pepper.
© 1995 Frances Bissell. All rights reserved.