4 green onions, cut into 1/2-inch pieces, white and green parts separated
1 tbsp ginger, finely grated
1 clove garlic, finely grated
1 lb Napa cabbage, about 1/2 head=1 lb, cut into 1-inch pieces
Cooked rice, for serving (optional)
1. Whisk egg white, 1 tbsp potato starch and 1 teaspoon soy sauce in a large bowl until frothy. Add the shrimp and toss to coat. Refrigerate 10 minutes. Meanwhile, whisk the hoisin sauce, vinegar, and the remaining 1 tablespoon soy sauce and 2 teaspoons potato starch in a small bowl, the whisk in the chicken broth. Set aside.
2. Drain the shrimp. Heat the vegetable oil in a wok or large skillet over medium-high heat, then stir-fry the scallion whites, ginger and garlic, about 30 seconds. Add the shrimp and stir-fry until almost cooked through,a bout 3 minutes. Add the cabbage and stir-fry until wilted and the shrimp are just cooked through, about 2 more minutes.
3. Stir the hoisin sauce mixture, then add to the wok and simmer, stirring occasionally, 2 minutes. Stir in the scallion greens. Serve with rice, if desired.