1. Drain the crabmeat, put the crab in a medium mixing bowl and set aside.
2. In a small bowl, whisk the egg, mayonnaise, mustard, Old Bay seasoning, lemon juice and 1/4 tsp. salt. Scrape the mixture over the crab and mix gently until well combined. Gently break up the lumps with your fingers but do not over mix.
3. Sprinkle the crushed corn flakes and the parsley over the mixture, and mix them in thoroughly but gently; try not to turn the mixture into a mash—it should still be somewhat loose. Cover with plastic wrap and refrigerate for 1-2 hours.
4. Shape the crab mixture into 8 football looking cakes about 1 inch thick. In a large nonstick skillet, heat the butter with the olive oil over medium heat. When the butter is frothy, add the cakes to the pan (8 should fit comfortably). Cook until dark golden brown on the underside, about 4 minutes. Flip the cakes, reduce the heat to medium low, and continue cooking until the other side is well browned, 4 to 5 minutes.