In a large bowl, mix the egg, yellow mustard, crab meat, old bay and mayo. Crumble the white bread and add to the bowl. Mix to combine and shape into 4 crab cakes
Add the crab cakes to a sheet pan and broil on high for 10 minutes. Add more old bay on top once broiled.
Once the crab cakes are done, get the sandwiches ready. I usually put a smear of the old bay mayo on the bottom bun of the potato roll. Then I add some shredded lettuce on top, followed by a jumbo crab cake on top. Top with the top bun of the potato roll and enjoy!