Gravlax is a festive dish and is used in a wide variety of ways. It is frequently served with a mild, sweet mustard-dill sauce: Gravlaxsås or Hovmästarsås (French: "maitre d'hôtel "sauce).
Common uses for gravlax are as the main dish with dill potatoes, by itself as a side, or part of another delicacy - like baked potatoes with shrimp and crawdad infused skagenröra. A favorite of mine, which my American friends find bizarre, is the smörgåstårta with gravlax (literally: sandwich cake). It is savory, not sweet and it is my birthday cake of choice.
Gravlax literally means "Buried Salmon" which comes from its roots in the Middle Ages. Originally gravlax was made by the local fishermen. Like other similar fish preservations dated from that time the fish was salted and fermented by burying it. The word gravlax comes from the Swedish word [gräva] (Eng: to dig "hole in the ground, ditch, grave").
Back in the Middle Ages the gravlax was only lightly fermented and was not given an overpowering fermentation flavor as in the infamous surströmming. Over time the fermentation part was ignored. Nowadays the burying part of gravlax is done by adding salt, sugar, white peppar and dill and curing it within plastic wrap or a zip-lock bag.
During the curing process there is wonderful osmosis magic that transforms the salmon. The drawn-out moisture transforms the dry rub cure into a concentrated dill infused brine. A very similar process is also used for curing wild game meats, which I should write about another time.
The grav-curing process can be made with all types of fatty fish. In Scandinavia, salmon is the most common fish that is cured this way.