Wash the roast and pat dry. Season all around with salt and pepper and place on the fat pan of the oven. Cook in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 1 hour.
In the meantime peel the vegetable onions and cut them into slices. After 30 minutes add them to the fat pan. After a further 15 minutes, pour 1/4 litre of water and tomato juice over them. For the vegetables, wash the cucumbers and cut them into bite-sized pieces.
Wash the beans, drain them. Heat the fat. Fry the cucumbers for 10 minutes, turning them over. Add the beans. Season with salt and pepper. Wash, chop and stir in parsley. For the sauce, pour stock through a sieve into a pot and bring to the boil.
Mix the flour with a little cold water until smooth. Bind the stock with it. Season to taste with salt and pepper. Refine with crème fraîche. Remove the netting. Arrange roast and vegetables garnished with parsley on a plate.
Pour some sauce over it. The rest of the sauce extra is fine.