Lightly grease a rimmed baking sheet with butter. Set aside.

In a large mixing bowl, whisk together mayo, egg, mustard, lemon juice, Old Bay, parsley, salt, and pepper until well combined.

Add crab meat and panko crumbs. Use a spatula to gently work the crab meat and panko into the wet ingredients (try not to break up the lumps of the crab meat, you want them to stay intact as much as possible).

Scoop crab meat by heaping ⅓ cup (about 3.15oz/90g per, I use my ice cream scoop) into a large scoop or measuring cup. I pack the meat into the scoop to help encourage it to keep its shape, then transfer to buttered baking sheet. If the crab cake is trying to fall apart, use your hands to press any stray pieces back in and pack it more firmly into the scoop next time. Do not flatten. Space at least 2” apart on baking sheet.

Place a small piece of butter on the top center of each crab cake.

Cover baking sheet tightly with plastic wrap and transfer to refrigerator to chill for at least 30 minutes and up to 24 hours before baking.

To bake: Preheat oven to 450F (230C). Once oven is fully preheated, remove crab cakes from refrigerator and remove plastic wrap. Transfer to center rack of oven and bake for 8-10 minutes/until baked through. For a browned exterior, switch oven to broil for the last 2 minutes and broil on high heat for 2 minutes (I do not switch my oven rack).