In a medium bowl, combine the peeled and deveined shrimp with buttermilk. Let sit for 10-15 minutes to help tenderize.

In a small bowl, whisk the listed sauce ingredients until combined. Set aside.

In a shallow bowl, whisk together the cornstarch, salt, garlic powder, and black pepper. Let the excess buttermilk drip off each shrimp, then coat evenly in the cornstarch mixture.

Heat vegetable oil in a 10-inch heavy-bottomed pan over medium heat to 350°F. Fry the shrimp in small batches for about 1 ½ minutes per side, until golden and crispy. Don't overcrowd the pan. Remove any browned bits from the oil between batches to prevent them from burning.

Transfer the fried shrimp to a wire rack to drain off excess oil and keep the crust crispy.