Combine salt, sugar, dill, gin and juniper berries in a bowl. Place two sheets of plastic wrap long enough to envelope salmon, ovelapping by hald, on your bench. Spread with half the salt mixture.
Top with the salmon fillet. Spread the rest of the salt mixture over the fillet. Wrap tightly and place on a platter (it always leaks, no matter how good a job you've done). Top with a smaller tray or board weighted with a couple of cans.
Refrigerate for 12 hours then remove weight etc. and turn the fillet over. Repeat every twelve hours or so for 48 hours - or 72, this recipe is very forgiving. When ready to serve, unwrap and wire clean of salt mixture then slice very thinly.
We like to top with a little of the accumulated juices as an extra flavour boost. Gravlax is at it's best when sliced paper thin - use a very sharp, fine bladed knife.