Be sure to chop the filling for these vegetarian dumplings with a knife; they become too wet and pasty in a food processor. We liked the dumplings boiled in water, but they're also delicious cooked in a steamer.
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
On a work surface, combine the chopped watercress, cabbage, scallions, garlic and pine nuts and finely chop them all together. Transfer the mixture to a bowl and season with the salt and white pepper. Knead the mixture slightly to wilt the greens.
Spread 6 gyoza wrappers on a work surface and brush the edges with water. Spoon 2 teaspoons of the filling into the center of each wrapper and fold in half; press the edges firmly to seal, pressing out any air pockets. Transfer the dumplings to a cornstarch-dusted baking sheet. Repeat with the remaining wrappers and filling.
In a pot of boiling salted water, cook the dumplings until tender and translucent, about 3 minutes. Alternatively, steam the dumplings on a rack set on a pan over boiling water. Serve the dumplings hot with soy sauce.
The uncooked dumplings can be frozen on a baking sheet, then transferred to a resealable plastic bag and frozen for up to 2 months. Boil or steam the frozen dumplings.