In a small bowl, whisk together the Seafood Seasoning ingredients. Omit this step if using Old Bay or similar.
In a medium bowl, combine the crab meat, bread crumbs, parsley flakes, and green onion.
In a separate bowl, whisk together the mustard, mayonnaise, egg, Worcestershire sauce, and 1 ½ tablespoons of the Seafood Seasoning blend or Old Bay.
Add the egg mixture to the crab mixture and mix well. Add more breadcrumbs if the mixture is too wet.
In a cast iron skillet, add about 1 inch of oil and preheat to 350 degrees F.
Dip out about ¼ cup of the crab mixture and form into a patty with your hands. If the mixture is too wet to handle, add a few more breadcrumbs. Cook for about 3 to 4 minutes, per side, or until a rich golden brown. Place on a wire rack to cool slightly. Serve warm with sauce, if desired.