Wash the parsley. Leave 3 leaves whole, cut remaining leaves into fine strips. Separate eggs. Beat egg whites until stiff. Stir in lemon juice and egg yolk. Sift cornflour over it and season with salt, pepper and nutmeg.
Brush the pan (22 cm Ø) with 5 g margarine, place parsley leaves in it and heat up. Pour egg foam mixture on top. Cover and let it simmer at low heat for about 20 minutes. In the meantime clean, clean and halve the mushrooms. Wash, clean, quarter and seed the tomatoes. Cut the flesh into strips. Heat 5 g margarine. Fry the mushrooms for about 5 minutes. Season with salt and pepper. Toss the tomato strips in it. Deglaze with broth, bring to the boil briefly.
Cut the flesh into strips. Heat 5 g margarine. Fry the mushrooms for about 5 minutes. Season with salt and pepper. Toss the tomato strips in it. Deglaze with broth, bring to the boil briefly. Cover half of the omelette with the mushroom mixture, fold the other half over. Sprinkle with parsley and serve