Preheat The Oven To 450 Degrees F (230 Degrees C). Line A Baking Dish With Parchment Paper. Combine Crushed Corn Flakes, Dill, Cayenne Pepper, Salt, And Ground Black Pepper In A Large Shallow Bowl. Brush Halibut With Mayonnaise To Evenly Coat On All Sides. Gently Press The Coated Halibut Fillets Into The Cornflake Mixture To Coat All Sides; Shake Off Any Excess. Transfer Breaded Halibut Fillets To The Prepared Baking Dish. Bake In The Preheated Oven Until Fish Flakes Easily With A Fork, 10 To 12 Minutes.