Wash the potatoes and cook in boiling salted water for about 20 minutes. Drain, rinse and peel. Put the vegetables in a hot pan without fat and fry over medium heat while turning for 6-8 minutes. In the meantime heat clarified butter in a second pan and fry the potatoes in it until golden brown. Season with salt and pepper.
Put the sauce in a small pot and heat it up. Wash parsley, dab dry and chop finely. Arrange the vegetables, potatoes, roast beef and sauce on two plates, sprinkled with fried onions and parsley. Sprinkle with pepper and serve garnished with parsley as desired. Add the rest of the sauce extra