Chinese Pepper Steak (Stir-Fried Beef With Onions, Peppers, And Black Pepper Sauce)

Ingredients

• 1 pound flank steak, skirt steak, hanger steak, or flap meat, cut into 1/4-inch thick strips
• 1/4 cup soy sauce (divided)
• 1/3 cup shaoxing wine or dry sherry (divided)
• 2 tablespoons corn starch
• 1/3 cup low-sodium homemade or store-bought chicken stock
• 1 tablespoon sesame oil
• 1 tablespoons sugar
• 1 tablespoon freshly ground black pepper
• 2 green bell peppers, cored and cut into 1-inch squares (about 2 cups)
• 1 red bell pepper, cored and cut into 1-inch squares (about 1 cup)
• 1 medium onion, cut into 1-inch strips from pole to pole (about 1 1/2 cups)
• 2 medium cloves garlic, finely minced (about 2 teaspoons)
• 2 teaspoons finely minced fresh ginger
• 3 scallions, whites only, finely minced
• 4 tablespoons vegetable, peanut, or canola oil
• kosher salt to taste