Clean lamb's lettuce and radicchio, wash thoroughly and drain. Remove melon seeds and cut out balls from the flesh with a ball cutter. Clean, wash and thinly slice the mushrooms.
Peel and finely dice the shallot. Wash the chicken meat and dab dry. Heat oil in a coated pan and fry the chicken fillets in it for about 10 minutes until golden brown all around. Season with salt and pepper and remove from the pan.
Add shallot, vinegar and 2-3 tablespoons of water to the frying fat. Bring to the boil briefly, remove from the heat and season with salt and pepper. Arrange the salad on a large plate. Cut the chicken fillets open and place them on the salad.
Spread lukewarm vinaigrette over it and serve sprinkled with parsley.