In Southern culture, you have to know how to fry seafood. It doesn’t matter if it’s fish, oysters or shrimp—you have to be able to fry one of them. One of the best ways to enjoy fried seafood in Cajun cuisine is on a dressed po’boy with a side of fries. We’re going to twice-cook these French fries before tossing them in a zesty seasoning.
Preheat the oven to 200 degrees F. Heat the oil in a large, deep heavy-bottomed skillet or Dutch oven over medium heat until a deep-fry thermometer registers 350 degrees F. Line 2 baking sheets with paper towels.
For the fried fish po’ boys: If using skin-on fish fillets, remove the skin, then cut into 4 equal pieces. Season each side of the 4 fillets with 1 teaspoon Creole seasoning. Whisk together the eggs, milk and 2 teaspoons of the Creole seasoning in a large shallow bowl, baking dish or cake pan. Whisk together the flour and the remaining 1 tablespoon of the Creole seasoning in a second large shallow bowl, baking dish or cake pan.
Dip 2 fillets in the egg mixture and carefully shake off any excess. Dip the fillets in the flour mixture and shake off any excess. Fry the fillets, flipping halfway through, until golden brown, 3 to 4 minutes depending on the thickness of your fish. Transfer the fish to the second prepared baking sheet and keep warm in the oven until ready to serve. Bring the oil back to 350 degrees F, then repeat with the remaining 2 fillets.
For the Cajun French fries: Cut the potatoes into 1 1/2-inch sticks and transfer to a large bowl of cold water. Stir until the water is cloudy. Drain the potatoes, transfer to one of the prepared baking sheets, top with paper towels, press down to blot and let sit until the potatoes are dry, 1 to 2 minutes.
Working in batches, gently add some potatoes to the hot oil, carefully shaking the skillet if needed to make sure the potatoes are completely covered with the oil. Fry until pale golden, about 2 minutes. Transfer the fries with a spider to the same baking sheet. Bring the oil back to 350 degrees F between batches.
Increase the temperature of the oil to 400 degrees F. Working in batches, add the fries and cook until golden brown, about 3 minutes. Transfer to the same baking sheet, sprinkle the Creole seasoning over top and toss with tongs.
To assemble the po’ boys: Evenly spread 1/4 cup mayonnaise on each baguette half. Place 1 cup lettuce, 1/4 cup pickles, half of the tomatoes, 2 fried fish fillets and hot sauce on the bottom half. Add some fries if desired, then add the top half. Repeat with the remaining baguette, lettuce, pickles, tomatoes, fried fish fillets and hot sauce.
For the Creole mayo: Stir together the mayonnaise, Creole seasoning and hot sauce in a small bowl. Serve with the po’ boys and Cajun French fries.