Rinse and pat dry the shrimp with paper towels. Set aside.
- In a bowl, whisk together the flour, cornstarch, baking powder, garlic powder, salt, and pepper. In a separate bowl, whisk the egg and buttermilk together.
- Dip each shrimp into the wet mixture (egg and buttermilk), then dredge in the dry flour mixture until well-coated. Repeat until all shrimp are coated.
- In a large skillet or deep fryer, heat vegetable oil to 350°F (175°C). Fry shrimp in batches for 2-3 minutes or until golden brown and crispy. Remove shrimp and place on a paper towel-lined plate to drain excess oil.
- In a small bowl, combine the mayonnaise, sriracha sauce, honey, rice vinegar, and garlic powder. Stir until smooth and well-combined.
- Once the shrimp are fried and crispy, place them in a large bowl. Pour the sauce over the shrimp and toss gently until all shrimp are coated.
- Transfer the Bang Bang Shrimp to a serving dish and garnish with chopped green onions or cilantro, if desired. Serve immediately.