Place cabbage in food processor, cover and finely chop. Sprinkle 1/4 teaspoon salt over cabbage in medium bowl. Let stand at room temperature 30 minutes. Squeeze excess water from cabbage. Mix together cabbage, ground pork, 1/2 teaspoon salt, egg white, cornstarch, white pepper, sugar, wine and 1 chopped green onion. Hold siu mai skin in hand. (Cover remaining skins with plastic wrap to keep them pliable.) Wet edge of half of the circle closest to fingers. Pinch 2 or 3 pleats into the wet edge. Place 1 heaping teaspoon pork mixture in center of skin. Fold circle in half, pressing pleated edge to unpleated edge to seal dumpling. Repeat with remaining skins. (Cover filled dumplings with plastic wrap to keep them from drying out.) Heat broth and 1/2 teaspoon sesame oil to boiling in Dutch oven. Reduce heat. Heat 4