Wash the chives, shake dry, cut into fine rolls. Finely slice Parmesan cheese. Mix lemon juice with 4 tablespoons of water and mustard, season with salt, pepper and sugar, fold in oil
Clean and trim the mushrooms, cut them into fine slices and spread them on 4 plates like roof tiles. Sprinkle mushrooms with dressing, serve sprinkled with parmesan and chives