Marinate the shrimp in buttermilk seasoned with Cajun seasoning, Dijon, and a couple whisked eggs.
Fill a bowl with a mixture of corn flour, panko, and Cajun seasoning.
Coat the shrimp on all sides with the panko mixture.
Chill the shrimp in a fridge for at least 15-20 minutes.
Fry the shrimp in batches for 2-3 minutes per side, until golden brown and crispy.
Immediately transfer the shrimp to a wire rack and sprinkle with flaky sea salt.
Prepare the po’ boy toppings so assembly is quick.
Spread a layer mayo or remoulade, add toppings, then lots of fried shrimp.
Place the top piece of bread on top, then enjoy hot!