1. Salt and rub the char fillets with the olive oil. Place them on a baking sheet with the skin side up.
2. Cook in the oven until the inner temperature reaches 44 degrees Celsius (110 degrees Fahrenheit).
3. Pull off the skin before serving.
4. Peel and slice the shallots thinly.
5. Cut the Savoy cabbage into strips, approx. four centimeters (one and 1/2 inch) wide.
6. Fry the shallots and cabbage until soft without taking on color. Add salt to taste.
7. Top the char with the onion and cabbage mixture, trout roe and plucked dill. Top with a generous amount of sauce.