Combine all the ingredients for the salt cure. Place the salmon in the cure mixture and let it rest for 15 minutes. Remove the salmon and pat dry.
Grill the salmon in a dry very hot frying pan for about 20 seconds on each side. Let it cool and place in the fridge.
Cut the salmon. Slice the apple thinly and grate the fresh horseradish. Arrange the salmon, apple, salmon roe, mâché salad, horseradish and creme fraiche on four plates. Serve with lemon and freshly grounded black pepper.