-crushed Cut the salmon in half lengthwise and remove the backbone and the small, freebones, as well, or ask your fish delaer to do it for you. Leave the skin on. Place half of the fish, skin side down, in a deep glass, enamel or stainless steel baking dish or casserle. Wash and then shake dry the bunch of dill and place it on the fish. (If the fill is of the hothouse variety and not very pungent, chop the herb coarsely to release it's flavor and sprinkle it over the fish instead.) In a separate bowl, combine the salt, sugar and crushed peppercorns. Sprinkle this mixture evenly over the dill. Top with the other half of the fish, skin side up. Cover with foil and set a heavy plate or platter on top of it, slightly larger than the salmon. Weigh it down with cans or jars and refrigerate for at least 3 days, up to 7 days. Turn the fish over every 12 hours or so, basting with the liquid marinade that accumulates, separating the halves a little to baste the salmon inside. Replace the platter and weights each time. When the gravlax is finished, remove the fish from it's marinade and scrape away the dill and seasonings. Pat dry with paper towels. Or leave the dill and seasonings in place. Place the separated halves skin side down on a carving board and slice the salmon thinly on the diagonal, detaching each slice from the skin. Gravlax is served as part of a smorgasbord or as an appetizer and is usually accompanied by a mustard-dill sauce (see recipe). When gravlax is presented as a main course, it is garnished with lemon wedges as well as the mustard-dill sauce and served with toast and perhaps a cucumber salad.