This Cajun-inspired appetizer can also be served on a platter with Creole sauce.
Whisk together mayonnaise, next 3 ingredients, and 1/2 tsp. Cajun seasoning in a small bowl.
Pour oil to depth of 3 inches into a Dutch oven; heat to 325°. Stir together batter mix and remaining 3 tsp. Cajun seasoning. Toss shrimp and buttermilk together in a large bowl. Dredge shrimp in batter mixture, shaking off excess. Arrange on a baking sheet.
Fry shrimp, in batches, 1 1/2 minutes on each side or until golden brown. Drain on wire racks over paper towels.
Thread 2 shrimp onto each skewer. Serve with Creole Sauce. Garnish, if desired.