In a medium bowl, whisk the egg white until slightly frothy. Add the shrimp and toss to coat evenly. In a separate bowl, combine cornstarch, flour, kosher salt, and 1/2 teaspoon freshly ground black pepper. Add the dry mixture to the shrimp and toss gently until each shrimp is lightly coated in a thin, even layer.

Aromatics & Seasoning Mix

Prepare aromatics

While shrimp rests briefly, thinly slice the garlic and separate scallion whites and greens. If using, thinly slice the jalapeño. Set aside in a small bowl: the sliced garlic, scallion whites, scallion greens, and jalapeño.

Flash-fry aromatics

Heat a wide skillet or wok over medium-high heat. Add 1 tablespoon of the neutral oil (taken from the measured cup) and when shimmering, add the sliced garlic and the scallion whites. Stir constantly for 15–30 seconds until garlic is fragrant and just beginning to color; remove these aromatics from the pan onto a plate lined with paper towel to drain. This step crisps the garlic and mellows the scallion whites; they will be tossed back with the shrimp.

Frying & Finish

Heat oil for frying

Pour the remaining neutral oil into a deep skillet or pot (about 1 cup total including the tablespoon used for aromatics). Heat over medium-high until the oil registers 350–365°F (175–185°C) on a thermometer, or until a small pinch of cornstarch sizzles vigorously on contact.

Fry shrimp (in batches)

Carefully add coated shrimp to the hot oil in a single layer without overcrowding. Fry 2–3 minutes, turning once, until the coating is golden and shrimp are opaque and just cooked through. Remove with a slotted spoon to a paper towel-lined plate. Repeat with remaining shrimp, keeping cooked shrimp warm in a low oven (200°F/95°C) if desired.

Final toss

Discard all but about 1 tablespoon of the frying oil from the pan, reserving the browned bits. Return the pan to medium-high heat, add the reserved 1 tablespoon oil plus 1 teaspoon sesame oil, then add the fried garlic and scallion whites back in and toss for a few seconds to reheat and perfume the oil. Add the fried shrimp and sliced jalapeño (if using). Sprinkle the remaining 1/2 teaspoon freshly ground black pepper and 1/2 teaspoon coarse/flake salt over the shrimp. Toss constantly for 20–30 seconds so the shrimp pick up the toasted garlic/scallion flavor and seasoning. Add 1 teaspoon light soy sauce and toss once to glaze lightly. Remove from heat.

Serve

Transfer shrimp to a serving plate. Scatter the scallion greens over the top. Serve immediately with lime or lemon wedges on the side to squeeze over shrimp if desired.