Step 1
Prepare the remoulade by combining all remoulade ingredients in a small bowl. Whisk together until well blended and season to taste with salt and pepper. Cover and refrigerate while preparing the rest of the sandwich.

Step 2
Pat the shrimp dry, then season with salt and pepper. In a large bowl, whisk together buttermilk, 1 tsp salt, 1/2 tsp pepper, onion powder, garlic powder, cayenne, flour, and hot sauce if using until smooth.

Step 3
Place cornmeal in another large bowl and line a baking sheet with parchment paper.

Step 4
Add shrimp to buttermilk mixture and toss until fully coated. Lift one shrimp at a time, let excess batter drip off, then transfer to cornmeal bowl. Toss until shrimp is evenly coated, then place on baking sheet. Repeat for all shrimp.

Step 5
Heat oil in a heavy-bottomed pot to 350°F. Fry shrimp in quarters until golden about 1 1/2 minutes per batch. Transfer to paper towel-lined plate and season immediately with salt. Continue frying remaining shrimp.

Step 6
To assemble sandwiches, spread remoulade on both cut sides of each loaf. Evenly divide fried shrimp, then top with shredded lettuce and sliced tomato. Serve immediately.