Wash lettuce, parsley and tomatoes and dab dry. Quarter the tomatoes. Pluck the lettuce into bite-sized pieces. Pluck parsley leaves from the stalks. Season vinegar and 2 tablespoons of water with salt, pepper and 1 pinch of sugar.
Add 2 tablespoons of oil. Place the salad ingredients in a bowl and mix with the vinaigrette. Wash the chives, dab dry and cut into small rolls. Mix crème légère, mustard and chives.
Season with salt, pepper and 1 pinch of sugar. Clean and slice the mushrooms. Peel onion and garlic and chop finely. Heat 1 tablespoon of oil in a frying pan and sauté the onion and garlic.
Add the mushrooms and fry them for about 5 minutes, turning them until golden brown. Remove and mix with the cream. Toast the bread. Place each slice on a plate and spread mushroom sauce on top. Arrange the salad on the plates.