Heat 2 inches of vegetable oil in a wide pot to 375 degrees F. Do not let the oil boil. If you do not have a thermometer, test the oil with a tiny drop of flour. It will immediately sizzle up.
Next, add the shrimp and buttermilk to a large bowl. Toss to coat the shrimp. Soak for a few minutes while the oil is heating.
Whisk together then cornstarch, cayenne (or paprika) and a bit of salt and pepper into a separate large bowl.
Drain the shrimp and shake off any excess buttermilk. Coat the shrimp in the seasoned cornstarch mixture, then fry them for 1 minute per side, or until they are cooked through and start to lightly brown.
Remove and drain the shrimp on paper towels.
Toss the shrimp with the bang bang sauce then garnish with fresh parsley and spicy chili flakes.
For Grilled Shrimp. Skip the frying and grill the shrimp instead. Heat your grill to medium heat and lightly oil the grates. Season the shrimp with a bit of salt and pepper (or use your favorite seasoning blend), then grill the shrimp 1-2 minutes per side, until cooked through. Then, toss them with the bang bang sauce.
For Sauteed Shrimp. Heat a tablespoon of vegetable oil in a saute pan. Season the shrimp with a bit of salt and pepper (or use your favorite seasoning blend), then saute the shrimp 1-2 minutes per side, until cooked through. Then, toss them with the bang bang sauce.