Crunchy Catfish Sandwich

Name: Crunchy Catfish Sandwich
Ingredients: 1 cup mayonnaise 1 lemon, juiced; 3 teaspoons prepared horseradish; 2 teaspoons hot sauce; 2 tablespoons dill relish; Pinch kosher salt; Pinch freshly ground black pepper; Oil, for frying; 2 eggs; 2 to 3 dashes hot sauce; 2 teaspoons seafood seasoning (recommended: Old Bay); Kosher salt; 1 cup cornmeal (medium ground for more texture); 1/2 cup all-purpose flour; 1/2 cup cornstarch Freshly ground black pepper; 4 catfish fillets, cut in 1/2, about 2 pounds; 4 sourdough sandwich rolls; 4 tablespoons butter, softened; 4 romaine or red lettuce leaves