1. Beat the egg and brush generously on the outside of the wheel of brie. Place corn flakes in a shallow bowl. Dip the egg washed brie into the cornflakes, pressing the brie gently to coat it as much as possible.
2. In a small sauté pan, melt the butter over medium heat. Once butter foams, add the corn flake-coated brie. Cook on each side until golden brown and crisp, about 5 minutes per side.