Clean and peel the carrots and celery. Clean and wash the leek. Cut vegetables into fine strips. Clean and clean the mushrooms, possibly wash and halve them. Peel and wash potatoes and cut them into 2-3 mm thick slices.
Wash parsley and dill, dab dry and pluck small bunches. Wash the cod and pat dry. Season strips of vegetables, potatoes, herbs and cod with salt and pepper. Knot one side of the oven tube tightly.
Pour prepared ingredients into the oven bag. Spread fat as flakes on top and pour on wine. Carefully close the oven bag (follow the instructions on the packet), place it on a cold oven rack, cut it and cook in the preheated oven (electric: 175 °C/ gas: level 2) for 20-25 minutes.
Remove, cut open the roasting tube and arrange 1 cod fillet each with vegetables, herbs and stock on plates.