Instructions

Whisk 2 tablespoons Shaoxing wine, ½ teaspoon salt, and ½ teaspoon white pepper together in bowl to dissolve salt. Pat four 4- to 6-ounce flounder fillets dry with paper towels, then place side-by-side in 13 by 9-inch baking dish. Pour wine mixture over top and let sit for 10 minutes. 
Whisk ½ cup chicken broth, 2 tablespoons soy sauce, 2 teaspoons sugar, 2 teaspoons toasted sesame oil, 1 teaspoon chicken bouillon powder, and remaining 2 tablespoons Shaoxing wine together in small bowl; set aside. Place ½ cup cornstarch in shallow dish. Working with 1 fillet at a time, lift out of marinade, letting excess drip back into dish, then transfer to dish with cornstarch. Flip fillet to coat both sides, pressing lightly to adhere; transfer to large plate. Repeat with remaining fillets.
Heat 2 tablespoons vegetable oil in 12-inch nonstick skillet over medium-high heat until shimmering. Add 2 fillets and cook, without moving, until golden brown on first side, about 3 minutes (if after 2 minutes fish is golden, reduce heat to medium). Using 2 spatulas, gently flip fillets and reduce heat to medium. Cook until golden brown on second side, about 3 minutes. Transfer to individual serving plates and sprinkle with 2 thinly sliced scallion greens. Repeat with additional 2 tablespoons vegetable oil, remaining fillets, and remaining scallion greens.
Wipe out skillet with paper towels. Heat remaining 1 tablespoon vegetable oil in now-empty skillet over medium heat until shimmering. Add 2 tablespoons minced fresh ginger and 4 thinly sliced scallion whites and cook until fragrant, about 30 seconds. Add broth mixture and cook for 30 seconds. Pour sauce evenly over each fish fillet on plates, then sprinkle with ½ cup chopped fresh cilantro. Serve.