Rinse shrimp, pat dry thoroughly with paper towels. Make 3 shallow slits on the underside of each shrimp (along the belly) and gently flatten slightly to keep them straight when frying. Leave tails intact for a handle. Lightly season shrimp with 1/2 tsp salt and 1/8 tsp black pepper.

Dust shrimp (optional)

Place rice flour or 1 tablespoon of all-purpose flour in a shallow bowl. Lightly coat each shrimp with a dusting — this helps the batter cling. Shake off excess.

Make batter

In a medium bowl, whisk together 1 cup all-purpose flour, 1/2 cup cornstarch, and 1/2 tsp baking powder with the remaining 1/2 tsp salt and 1/8 tsp black pepper. In a separate bowl, combine the lightly beaten egg and 1 cup ice-cold club soda. Quickly pour the wet mixture into the dry ingredients and stir with chopsticks or a fork just until combined — small lumps are fine. The batter should be cold and slightly thin; do not overmix (overmixing develops gluten and makes batter heavy). Keep batter chilled over an ice bath if your kitchen is warm.

Heat oil

Pour vegetable oil into a deep pot or Dutch oven to a depth of about 2 inches (or use a fryer). Heat oil to 350°F (175°C). If you don't have a thermometer, test by dropping a little batter into the oil — it should sizzle and rise immediately without burning (aim for steady bubbling).

Fry shrimp

Working in small batches (4–6 shrimp at a time to avoid crowding), hold each shrimp by the tail, dip into the batter to coat, letting excess drip back into the bowl, then carefully slide into the hot oil. Fry until batter is crisp and pale golden, about 2.5–3 minutes depending on shrimp size. Turn as needed for even color. Remove with a slotted spoon or spider and drain on a wire rack set over a baking sheet or on paper towels. Keep finished shrimp in a warm (200°F / 95°C) oven if needed while frying remaining shrimp. Repeat until all shrimp are cooked.

Finish

Once all shrimp are cooked, optionally double-fry for an extra-crisp shell: return shrimp to 375°F (190°C) oil for 30–45 seconds, then drain. Sprinkle with a light pinch of salt while hot.

Spicy Citrus Aioli

In a small bowl, combine 1/2 cup mayonnaise, 2 tablespoons sour cream (or yogurt), 2 teaspoons fresh lime juice, 1 teaspoon orange zest, 1 clove grated garlic, 1 tablespoon Sriracha, 1/2 teaspoon gochujang (if using), 1/2 teaspoon honey, 1/4 teaspoon sesame oil, 1/4 teaspoon salt, and 1/8 teaspoon black pepper. Whisk until smooth. Taste and adjust heat or acidity: add more Sriracha for heat, more lime for brightness, or a touch more honey if too sharp. Chill in refrigerator for at least 10 minutes to allow flavors to meld.

Garnishes & Assembly

Plate 4–6 shrimp per serving. Spoon or pipe the spicy citrus aioli alongside or into a small dipping dish. Sprinkle sliced scallions and toasted sesame seeds over the shrimp and around the plate. Serve with lime wedges for squeezing over the shrimp for extra brightness.

Serve immediately while tempura is hot and crisp. Leftovers (battered/fried shrimp) will lose crispness; reheat briefly in a hot oven (425°F / 220°C) for 5–7 minutes to regain some crunch.