Peel onion and cut into thin rings. Clean, wash and quarter the radishes. Cut Gouda into sticks. Clean, wash and cut the salad into strips. For the vinaigrette mix mustard, mayonnaise and vinegar. Season with salt, pepper and sugar.
Whip olive oil into it. Wash the meat and dab dry with kitchen paper. Heat the oil in a small pan and fry the meat in it over medium heat for about 2 minutes on each side. Then season with salt and pepper. Cut the meat into wide strips. Mix the radish, lettuce and onions, place in a small plate, spread strips of meat and cheese over it and pour the vinaigrette over it