Position an oven rack in the lower third of the oven and heat the oven to 425°F (220°C).
In a medium bowl, whisk the egg, mayonnaise, mustard, hot sauce, Worcestershire sauce, paprika, and salt until smooth.
Stir in the red bell pepper, green onion, and parsley.
Drain the crab and pat it dry, then gently fold it into the bowl with the panko until just combined, keeping the crab in large pieces.
Cover the bowl and refrigerate for 10 minutes.
Lightly grease a rimmed baking sheet with oil or cooking spray.
Shape the mixture into 3 patties, pressing each one firmly, and set them on the baking sheet.
Refrigerate the patties for 10 minutes.
Bake for 10 minutes, until the bottoms are golden and lift cleanly with a thin spatula.
Flip and bake for another 8 to 10 minutes, until golden on both sides.
Squeeze fresh lemon over the crab cakes and serve.
Notes
Buy lump crab and pick through it: Lump crab gives you the biggest, sweetest pieces. Even crab labeled fresh-picked can hide a small piece of shell or cartilage, so run your fingers through it before it goes in the bowl.Mix the base before the crab goes in: Whisk the egg, mayonnaise, and seasonings into a smooth base first, then fold in the crab and panko with a few gentle strokes. The less you stir once the crab is in, the bigger the lumps stay and the lighter the cakes bake up.Give the cakes room on the pan: Three cakes fit easily on a small rimmed baking sheet. Leave a little space around each one so the edges brown.Start checking early: Ovens run differently, so begin checking your cakes around the 10-minute mark rather than waiting out the full bake. Yours may be ready a couple of minutes sooner or later.