Clean and wash the leek and cut into thin rings. Heat 1 tablespoon of oil in a frying pan. Sauté the leek in it for about 5 minutes. Add white sauce and bring to the boil. Spread in a flat roasting pan
Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Rinse fish
and pat dry. Season inside and outside with salt and pepper. Place on the leek vegetables. Cover with bacon. Bake in a hot oven for about 45 minutes. Sylter La-Ratte boiled potatoes taste great with this