For the graved salmon trout fillet, carefully debone the salmon trout fillet. Place one fillet skin side down on a board. Mix sea salt, sugar, peppercorns and juniper berries with the chopped dill and spread on the fillet.
Place the second fillet on top, place together in a freezer bag and seal. Place fillets between two boards and weigh down. Marinate in refrigerator for about 48 hours, turning once in between.
To serve, scrape salt, sugar and dill from fish. Finely slice salmon trout fillets with a salmon knife and serve with sauce.
For the sauce, whisk or blend all ingredients until smooth and season to taste.