In a shallow rimmed dish, combine the first 7 (dry) ingredients. In a separate shallow rimmed dish, pour in beaten egg.
In a Dutch oven, fill a ⅓ of the way up with vegetable oil. Heat oil to 350 degrees.
One at a time, take oysters and dip in flour mixture, shaking off excess, then dip in egg mixture. Put oyster back in flour mixture, fully coating the oyster.
When oil is ready, place oysters in oil, being careful not to crowd the pot. Fry on one side for 1 minute, then flip oysters over and fry for one more minute. Do not over fry as that ill cause the oyster to toughen and burn.
Toast sandwich buns. Spread mayonnaise on each side of bun. Place desired amount of oysters in bun. Top with lettuce.
Po Boys are best when served warm.
Recipe by Farmhouse 1820 at https://farmhouse1820.com/oyster-po-boy/