
Boil the potatoes until tender, probably 40min or so.
Pour the water out and let the potato steam itself and naturally dry the exterior.
Cook the arctic char skin side down in oil. When the fish is half way cooked, add in potato and butter.
Once things are close to done, add lemon to the bottom of the pan and vegetables, cook the rest of them. You may want to cover the pot if you want the vegetables to steam.