Heat 3-4" of oil to 350 F in a deep fryer or Dutch oven.
In a pie plate or shallow dish, whisk together the buttermilk, egg, and mustard.
In another pie plate or shallow dish, whisk together the flour, cornmeal, paprika, salt, cayenne and garlic powder.
Working in batches, add the shrimp to the flour mixture and coat well.
Shake off excess then place into the buttermilk mixture.
Shake off excess then return to the flour mixture, coating again.
Add to the hot oil and fry 3-4 minutes or until golden brown, turning once. Remove to a paper towel-lined plate to drain.
Serve with the spicy remoulade sauce.