Preheat the oven to 200 ° C. Rub the roast all over with pepper and salt and fry in hot oil in a roasting pan on the stove. Dice the onions, put them in the roaster and sauté them. Put the roaster in the oven. Gradually pour in the water and beer. Fry for a total of about 2 hours.
Put the peeled potatoes in the roasting pan after 75 minutes, season with salt and caraway seeds. Baste everything with sauce more often. Wash the leek and cut into rings. Place in the roaster 30 minutes before the end of the cooking time.