Drain the crabmeat, if necessary, and pick through it for shells ( jumbo lump will not have shells). Put the crab in a medium mixing bowl and set aside.

In a small bowl, whisk the egg, mayonnaise, mustard, Old Bay seasoning, lemon juice, Worcestershire sauce, 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 overmix.

Sprinkle the breadcrumbs 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 to 3 hours.

Shape the crab mixture into 8 cakes about 1 inch thick. In a 12-inch 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. Serve with lemon wedges on the side for squeezing over the cakes.