Recipe courtesy of the Mushroom Council and mushroominfo.com
2 tablespoons corn oil margarine
3/4 cup onion, chopped
1 1/2 pounds white button mushrooms, thinly sliced
1/3 cup dry Sherry
1 1/3 cup skim milk
3/4 cup all-purpose flour, unbleached
3 large egg whites
1 large egg
1/2 tablespoon thyme leaves, crushed
1/4 tablespoon salt
1/4 tablespoon freshly ground black pepper
1/2 cup parmesan cheese, freshly grated
Preheat oven to 350° F. Using a nonstick vegetable spray, spray a 10-inch fluted quiche pan or pie plate.
For the filling: In a large skillet heat margarine until melted. Add onion; cook over medium-low heat, stirring occasionally, until onion is just softened, about 3 minutes. Add mushrooms and dry Sherry; cook, stirring frequently, until liquid has evaporated, 15 to 18 minutes; set aside.
Meanwhile prepare the crust: In the container of an electric blender place milk, flour, egg whites, egg, thyme, salt and black pepper. Blend on high speed, until well beaten, 1 to 2 minutes. Pour 1 cup mixture into prepared pan forming a thin layer; set remaining mixture aside. Bake until firm to the touch, about 10 minutes.
Remove from oven; transfer to a baking sheet; spoon mushroom mixture from skillet evenly over crust reserving 1/4 cup mushrooms for garnish; sprinkle with parmesan cheese. Whirl remaining milk mixture in blender to combine; pour over cheese. Bake until puffed and brown, about 45 minutes.
Remove from oven; allow to cool, about 10 minutes before serving (clafouti will lose some of its puffiness and flatten out). Garnish with reserved 1/4 cup mushrooms and fresh thyme springs, if desired. Serve warm or at room temperature.