Wickles Spicy Shrimp Po'Boys

Ingredients

• 4 6- inch lengths baguette, split
• 2 tbsp butter, at room temperature
• 2/3 cup mayonnaise
• 2 1/2 tbsp Dijon mustard
• Cooking oil, for frying
• 1/2 cup whole milk
• 1 egg, beaten to mix
• 3/4 cup dry bread crumbs
• 1/2 tsp salt
• 1/4 tsp fresh-ground black pepper
• 1/4 tsp cayenne
• 1 1/4 pounds large shrimp, shelled
• 1/3 cup flour
• 2 cups shredded romaine or iceberg lettuce
• 1 tomato, cut into thin slices
• 2 tbsp Spicy Red Sandwich Spread