Cabbage Watercress and Pine Nut Dumplings

Name: Cabbage, Watercress and Pine Nut Dumplings
Ingredients: 1 1/2 cups (packed) coarsely chopped watercress; 1 1/2 cups (packed) coarsely chopped napa cabbage; 2 scallions, finely chopped; 2 garlic cloves, minced; 1/4 cup plus 2 tablespoons pine nuts, finely chopped; 1 teaspoon kosher salt; 1/4 teaspoon freshly ground white pepper; One 12-ounce package gyoza wrappers or wonton wrappers; Cornstarch, for dusting; Soy sauce, for dipping