Lay the salmon fillets, skin side down, on a board and brush your hand along it.
If you feel any pin bones pinch them out with your fingers or tweezers.
In a bowl, mix all of the other ingredients for the salmon together to make the cure.
Stretch two large sheets of cling film over a work surface and spoon over some of the cure.
Lay one of the fillets, skin side down, on the cure, then pack over most of the cure, and sandwich with the remaining fillet, skin side up.
Top with the last of the cure and wrap both fillets together tightly with lots of cling-film.
Place in a large roasting tray, put a smaller tray on top and weigh it down with a couple of tins.
Leave in the fridge for at least three days or up to a week. Once a day, pour away any excess liquid, turn the salmon and re-apply the weights.
To serve, unwrap the salmon from the cling film and brush off the marinade. Slice the salmon into thin slivers