For pancake batter: Sift flour into bowl, season with salt and pepper. Slowly beat in whole egg, egg yolk, and milk. Set aside for 4 hours in cool place. When ready to cook, melt 2 tablespoons butter in small omelet pan and pour in batter, covering base with a thin layer. Cook each side until light brown. Make 4 pancakes total. Keep them warm.
Preheat broiler. Melt 3 tablespoons butter in heated pan and add flour. Cook 3 minutes, without coloring. Slowly stir in 1/2 of fish stock and bring to a boil. Add remaining stock and reduce heat and simmer. Season with salt and white pepper.
Meanwhile, heat clarified butter in frying pan and add mushrooms. Fry gently. Add lemon juice and salt and pepper. Add tomatoes and simmer gently.
To fish sauce, add cream and cheese, stirring thoroughly to melt cheese. Add sherry, then tomato and mushroom mixture. Cover fish with sauce.
Place crepe on serving dish, top with sauced fish in center and roll up. Repeat with remaining pancakes. Once rolled, pour remaining sauce over top of crepes and place under broiler for 2 minutes to brown.