Cut the ready-to-cook salmon in half lengthwise and remove the center bone. Briefly rinse and dry the salmon halves. Place one fillet, skin side down, in a large enough bowl and sprinkle with the dill. Combine the salt, sugar and pepper and sprinkle over the top. Place the other half of the salmon, skin side up, on top. Cover with aluminum foil and weigh down (see note). Place in refrigerator for 24 hours. Marinate for another 3-4 days in the refrigerator, turning the fish a couple of times a day to the other side and baste with the liquid that comes out.
For the sauce, mix all the ingredients well.
Remove the salmon from the marinade, scrape off the dill and spices and dry the fish. Cut diagonally into thin slices and bring to the table with the sauce.
Serve with toast and green leaf salad.
Note: According to translation of most gourmets, not only in Scandinavia, the preparation of salmon as gravet laks does best justice to the pink-colored noble fish. The name goes back to the original method of preserving dry salt, in which the fish was sprinkled with salt, sugar and pepper and covered with dill and buried (gravet) in a hole in the ground for several weeks, whereby the seasoning ingredients were absorbed into the salmon under the pressure of the applied earth. In the normal household it is recommended to weigh down a plate or possibly a thick wooden board and pre-cooled tin cans as weight