Slice across the fish fillet, not through it, making several shallow cuts in the fillets to help absorb the following marinade.
Mix salt, peppercorns, and sugar and generously coat the body of the fillet, flipping it over to get both sides equally. Dice the dill, and do the same, covering both sides.
Wrap in foil or plastic, then place in refrigerator with a weighted pan on top to help the fish better absorb the marinade.
Allow to stay in refrigerator for 2 to 3 days before serving, flipping twice per day while basting with the liquid that pools around the fish.
Smaklig måltid!
Notes
Top it with Hovmästarsås, a dill-infused mustard sauce most notably used with this salmon dish.