I'm in the UK in an area where local fishmongers are unreliable and untrustworthy so for smoked salmon I am using farmed Scottish salmon sides, bones-out but skin-on, supplied by a major national supermarket fresh vacuum-packed in their factory. I have high confidence in the cleanliness, age and provenance of the fish. Nevertheless, our National Health Service has carried out a study into parasites and concluded that both wild and farmed salmon may carry parasites. The NHS says that freezing the salmon below minus 15 Celcius for at least two days will kill all parasites that are likely to be found in salmon from British waters.
So I have bought two 500g 'sides' of fresh vacuum-packed salmon and I presently have them in the freezer at -18C. All instructions I've read are dry or wet curing from fridge temperature - i.e. not rock hard at -18C. I propose to prepare a glass rectangular bowl with a base layer of dry salt/sugar cure (50% salt 50% sugar) then the first side of salmon, then second layer of dry cure, second side of salmon and finally the last layer of dry cure, a bit like making lasagne, then I am hoping the salt will start to melt the ice crystals, pulling the temperature down probably to a slushy mix at around -20C --- rather like salted road surfaces in winter.
I see the benefit being that we don't have to let the product get anywhere near the danger temperature while it defrosts at any stage. I would then plan to have it ready to go into the fridge at a time it can be left unattended for its cure time, then rinse, dry and smoke in the usual way.
It's possible that this is a known method and either has problems or snags and work-arounds....
Thanks for bearing with me for a rather long and detailed post -- and my first post on this forum as well!! :)