Wash and finely chop herbs. Peel the onions and cut into thin rings. Clean and wash the carrots and mushrooms. Cut the carrots into slices and the mushrooms into quarters.
Heat the fat. Fry the onions and mushrooms in it. Sauté the carrots, peas and half of the herbs. Season with salt and pepper. Deglaze with stock and wine. Bring to the boil and simmer for approx. 5 minutes.
Wash the trout and pat dry well with kitchen paper. Season with salt, pepper and lemon. Add the rest of the herbs to the trout. Put the vegetables and trout in an ovenproof dish, pour the cream over them.
Cover and bake in a preheated oven (electric stove 200 degrees / convection 175 degrees) for 20 minutes.