Peel, wash and cut the potatoes into pieces. Cut the sausages in half. Heat the oil in a pan and fry the sausages for 5-6 minutes. Take them out and put them aside. Add potatoes to the frying fat and fry over medium heat for about 15 minutes, turning several times. In the meantime, clean and wash the leek and cut into rings. Cook peas in boiling salted water for 2-3 minutes.
Drain, chill and let them drip off. Clean, wash and quarter radishes. Add leek to the potatoes and fry for 8-10 minutes more. Season to taste with salt and pepper. Mix in peas. Cut the cress from the bed, sprinkle over the pan with the radishes