Wash the meat, dab dry and rub with salt and pepper. Peel and slice the onion. Rinse the fat pan of the oven with water, place the meat and onion on top.
Roast in the preheated oven (electric cooker: 200°C/ gas: level 3) for 1 1/2 - 1 3/4 hours. In the meantime, clean, wash and cut the peppers into rhombs. Clean the oyster mushrooms. Carefully wash marjoram, dab dry and pluck off the leaves, except for a few stalks for garnishing.
Halfway through the frying time, pour on 1/4 litre of broth and ladle the roast. Approx. 20 minutes before the end of the frying time, spread the paprika, oyster mushrooms and marjoram around the roast and braise it as well. Keep the finished roast warm.
Lift the vegetables out of the fat pan. Dissolve the roast with the remaining stock and cream. Pour into a saucepan and bring to the boil. Add sauce thickener and bring to the boil again briefly. Season to taste with salt, pepper and paprika powder.
Arrange meat and vegetables on a plate. Put some sauce on the meat and serve garnished with marjoram. Serve the rest of the sauce separately.