Fresh pieces of salmon are marinated (cured) in sugar, salt, dill and black pepper.
You can buy it prepared or make your own.
Some recipes for making your own will have you let the salmon pieces sit in the marinade for 3 to 4 days either in the fridge or at a temperature between 3 and 4 C. The salmon pieces are turned twice a day. See health note below in Nutrition regarding curing times.
Gravlax that is first cured as above, then hot-smoked. The smoking process changes the taste, but will kill any parasites or tapeworms possibly in the fish.
As in eating other raw fish, such as sushi or ceviche, there is a risk of parasites or tapeworms in eating Gravlax. Many recipes call for Gravlax to be cured for 7 days, which some say would also meet the safety requirements. When making your own raw fish dishes at home, however, health ministries of various governments advise starting with commercially frozen fish to negate the risk. See the main entry on Fish, under Nutrition.
“Lachs” or “lax” means salmon; “graved” means buried. It used to be that the salmon was just buried in sand on the shore.
Gravadlax (gravad lax) is Danish; gravlaks is Norwegian.