Preheat the oven to 400°F and coat a shallow baking pan with nonstick spray.
Drain the crab in a colander and using your fingers, pick through it to remove any bits of shell that might remain after processing.
Transfer the crab to a mixing bowl, then add the panko crumbs, mayonnaise, lemon juice, and scallions and combine. Season to taste with salt and pepper, then add the egg and combine thoroughly.
Gently but firmly, pack some of the crab mixture into a 1/3 cup measure that has been coated with nonstick spray.
Turn the measuring cup upside down and tap it gently until the formed crab cake comes out.
Using your hands, gently firm the mixture into a patty and place it on the prepared baking sheet.
Repeat the process with the rest of the crab mixture - you should end up with 6 crab cakes.
Bake the crab cakes for 10 minutes, then remove them from the oven and carefully turn them over.
Continue baking for an additional 10 minutes or until golden and crisp on the outside.
Serve immediately with cocktail and/or tartar sauce and lemon wedges.