Clean mushrooms by wiping with a damp cloth or quickly rinsing and patting dry. Trim and discard tough stems. If using large shiitakes, slice into 6–8 mm (1/4–1/3 in) thick pieces so they fry evenly; if using black fungus, tear into bite-size pieces and drain thoroughly.

Marinate

Place mushrooms in a bowl. Add 1 tablespoon light soy sauce, 1 tablespoon rice wine (or sherry), 1 teaspoon sesame oil, 1 teaspoon ground black pepper and 2 teaspoons cornstarch. Toss to coat evenly. Let sit 10–15 minutes — cornstarch helps create a silky base that the coating will adhere to.

Crunchy Coating

Make Dry Coating Mix

In a shallow wide bowl or plate whisk together 1 cup all-purpose flour, 1 tablespoon cornstarch, 1/2 teaspoon baking powder, 1 teaspoon fine salt and 1/4 teaspoon white pepper until uniform.

Make Batter

In a separate bowl lightly beat 1 large egg. Add 3 tablespoons cold sparkling water and whisk briefly to combine. The batter should be slightly loose but clingy; if it seems thick, add 1 teaspoon more cold water. The egg batter will be used as a binding layer before dredging in the dry mix.

Coat Mushrooms

Working in batches to avoid overcrowding, toss marinated mushrooms in the egg-sparkling water mixture to coat, then dredge thoroughly in the dry flour/cornstarch mix, shaking off excess. Place coated pieces on a wire rack while you heat oil.

Frying & Glaze

Heat Oil

Pour about 3–4 cups (approx. 600 ml) neutral oil into a heavy-bottomed skillet or wok to a depth of ~1–1.5 inches (2.5–4 cm). Heat oil over medium-high until it reaches 175–185°C (350–365°F). If you don’t have a thermometer, test with a small piece of coating: it should sizzle and rise steadily.

First Fry (Blanch Fry)

Fry coated mushrooms in batches, 4–6 pieces at a time depending on pan size, for 2–3 minutes until they are set and lightly golden but not deeply browned. Remove with a slotted spoon to a wire rack or paper towel-lined tray and rest for 2–3 minutes. This step cooks them through without burning.

Second Fry (Crisping)

Increase heat slightly if needed and return mushrooms to hot oil in batches for a second fry, 1–2 minutes until deeply golden-brown and crisp. Remove to a wire rack to drain. Double-frying yields a very crisp exterior.

Make Glaze

Discard all but 1 tablespoon of the frying oil from the pan (cool slightly first), or use a clean skillet. Heat that 1 tablespoon over medium; add 1 teaspoon minced garlic and sauté 10–15 seconds until fragrant (do not burn). Add 1 tablespoon soy sauce, 1 tablespoon oyster sauce, 1/2 teaspoon dark soy (optional), 1 teaspoon sugar and 2 tablespoons water. Stir and bring to a gentle simmer for 30–45 seconds until sugar dissolves and sauce slightly thickens.

Toss with Glaze

Add the fried mushrooms to the glaze and quickly toss or stir for 20–30 seconds so each piece gets a light glossy coating. Remove immediately so coating stays crisp. Stir in 2 tablespoons thinly sliced green onions and 1 teaspoon toasted sesame seeds.

Plate and Garnish

Transfer mushrooms to a serving plate. Sprinkle with chopped cilantro (or parsley). Serve with lemon or lime wedges and optional chili flakes or sliced fresh chili for heat. Serve immediately to preserve crispness.