Cut the maties into cubes, peel and finely dice the onion. Wash and dry apple, cut into quarters, remove core and dice. Dice mustard cucumber. Wash, clean and finely slice radishes. Add onion, apple, mustard cucumber, radish to the matie, add lime juice and oil and mix everything well. Season the matie salad with salt, pepper and sugar. Cut cress from the bed and add to the salad. Cover the matie salad with cling film and put it in the refrigerator for about 1 hour. Spread bread with brunch and spread the matie salad on it. Garnish each slice of bread with a bunch of cress.