Clean, wash and drain the salads. Pluck large leaves smaller. Grate parmesan. Wash and halve the tomatoes. Peel and halve the onion and cut into fine strips.
Wash the meat, dab dry. Fry in 1 tablespoon of hot oil on each side for about 3 minutes. Season with salt and pepper.
Meanwhile, for the vinaigrette, mix vinegar, 1 tablespoon of water, salt, pepper and 1 pinch of sugar. Fold in 2 tablespoons of oil. Mix the lettuce, tomatoes and onion with the vinaigrette. Cut the meat into strips and arrange on the salad.
Sprinkle with cheese.