Pat shrimp dry with paper towels. Season lightly on both sides with 1/2 tsp kosher salt, 1/4 tsp black pepper and 1/4 tsp garlic powder. Set aside in a single layer while you prepare the batter and dredge station.

Breading & Dredging

Set up dredging

In a shallow bowl combine 1/2 cup flour, 2 tbsp cornmeal (if using), and a pinch of salt and pepper. This is for a first light dusting to help the batter adhere.

Dredge shrimp

One by one, lightly toss each seasoned shrimp in the flour mixture, shaking off excess. Place dredged shrimp on a tray; keep refrigerated if not frying immediately.

Make Beer Batter

Combine dry ingredients

In a medium bowl whisk together 3/4 cup flour, 2 tbsp cornstarch and 1/2 tsp baking powder until homogenous.

Add wet ingredients

Stir in the beaten egg, 1/2 cup ice-cold beer and 2 tbsp cold club soda. Add 1/2 tsp hot sauce if using. Mix gently until just combined — small lumps are okay. Batter should be thick enough to coat the back of a spoon but pourable; if too thick add 1 tbsp more beer or soda. Keep batter chilled until ready to use.

Frying

Heat oil

Pour 3 cups vegetable oil into a heavy-bottomed pot or deep skillet to a depth of about 2–3 inches. Heat to 350°F (175°C). If you don’t have a thermometer, oil should bubble steadily when a small drop of batter is added and sink slowly.

Batter and fry shrimp

Working in batches (do not overcrowd), dip each dredged shrimp into the beer batter, letting excess drip off briefly, then carefully lower into the hot oil. Fry 3–4 shrimp at a time for 2–3 minutes until golden brown and crisp. Use a slotted spoon to remove shrimp and transfer to a wire rack set over a baking sheet or paper towels to drain. Keep fried shrimp warm in a low oven (200°F/95°C) if frying multiple batches.

Make Boom Boom Sauce

Combine sauce ingredients

While shrimp fry, whisk together 1/2 cup mayonnaise, 2 tbsp sweet chili sauce, 1 1/2 tbsp sriracha, 1 tsp hoisin, 1 tsp lime juice, 1 tsp rice vinegar, 1 tsp honey, 1 tsp minced garlic, 1/2 tsp sesame oil, 1/8 tsp salt and a pinch of black pepper in a bowl until smooth. Taste and adjust heat or sweetness to preference. Chill briefly if prepared ahead.

Tossing & Finish

Toss shrimp in sauce

Place 10 hot fried shrimp in a large bowl. Spoon about 1/3 to 1/2 cup of the Boom Boom sauce over the shrimp (reserve any extra for serving). Gently toss until shrimp are evenly coated. The shrimp should be saucy but not swimming; adjust amount to preference.

Plate and garnish

Transfer sauced shrimp to a serving plate. Sprinkle with 1 tbsp thinly sliced green onions and 1 tsp toasted sesame seeds. Serve immediately with lime wedges on the side and extra sauce for dipping.