For the remoulade sauce: In a blender, combine the garlic, egg, green onions, prepared mustard and vinegar; blend to a smooth puree. With the motor running, very slowly drizzle in the olive oil until emulsified into an aioli.
Combine the ketchup, paprika, horseradish, dry mustard, salt and cayenne in a mixing bowl. Fold in the aioli, and mix well.
For the po'boy: Heat the oil in a medium saucepot until it reaches 350 degrees F on a deep-fry thermometer.
Lightly bread the shrimp and oysters by tossing in the breading mix. Carefully add the seafood to the hot oil, working in batches if necessary. Cook until golden brown and cooked through, 3 to 5 minutes.
Toast the hoagie rolls. To the toasted rolls add the lettuce, tomato and red onion, and then drizzle remoulade sauce over the vegetables. Top with the fried shrimp and oysters, and serve with lemon wedges.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.