Preheat oven to 500°.
Sprinkle 1 tablespoon flour and salt over 1 side of fillets. Place fillets, flour sides up, in a 13 x 9-inch baking dish coated with cooking spray.
Combine 1/2 cup flour and pepper in a medium bowl. Gradually add beer, oil, and egg yolk, stirring with a wire whisk until blended.
Beat egg whites at high speed of a mixer until stiff peaks form. Gently fold egg whites into beer mixture, and spread evenly over fillets. Bake at 500° for 10 minutes.