Preheat the oven to 200 degrees. Place the roast with the rind on the bottom of the pan and sear over medium heat for 15 minutes. Fry the remaining sides for 5 minutes each. Now sprinkle with salt and pepper and place with the rind side down in the roasting pan. Pour the vegetable stock and beer over them and add the marjoram. Cook in the oven for 30 minutes.
Now clean and peel the potatoes, carrots and parsley. Cut the potatoes into 1.5 cm pieces, cut the onion into rolls, press the garlic and cook everything in the vegetable stock. Turn the roast over and add to the vegetable stock. Cook for another 60 minutes. Finally, collect the liquid (drain the vegetables with a sieve).
Add the parsley to the sauce, add the sauce thickener and season with salt and pepper. Now put the vegetables back into the sauce, cut the meat into slices and add the potato vegetables.