- Portion size 16 servings
Steamed Bun Dough:
Steamed Bun Dough: In large bowl, dissolve sugar in water. Sprinkle in yeast; let stand until frothy, about 10 minutes. Stir in salt. Mix in enough of the flour to make soft ragged dough. Turn out onto floured work surface. Knead, adding as much of the remaining flour as necessary, until smooth, elastic and no longer sticky to the touch, about 8 minutes.
Place in greased bowl, turning to grease all over; cover and let rise in warm draft-free place until doubled in bulk, about 3 hours.
Punch down dough; turn out onto lightly floured surface. Flatten slightly and sprinkle with baking powder. Knead into ball, incorporating baking powder completely, about 1minute. Cover and let rest for 10 minutes.
Meanwhile, place cabbage in large bowl. Sprinkle with salt ; toss. Let stand for 20 minutes. In separate bowl, cover mushrooms with hot water; soak until soft and pliable, about 20 minutes.
Squeeze cabbage by handfuls to remove water, then transfer to large bowl. Discard cabbage liquid. Remove mushrooms from water, squeezing liquid back into bowl. Cut off stems; save soaking liquid and stems for another use. Slice caps thinly; add to cabbage along with pork, onions, egg, soy sauce, oil, hot pepper flakes (if using) and pepper. Toss to combine; set aside. (Make-ahead: Cover and refrigerate for up to 1 day.)
Roll out dough into 16-inch log. Slice into 16 pieces; roll or press each into 3-inch circle. Spoon scant 2 tbsp filling onto centre of each circle. Gather dough together around filling, stretching slightly if necessary, to form pouch; twist to seal top.
Cut sixteen 3-inch squares of parchment paper. Place each bun, sealed side up, on square of paper. Arrange in steamer trays, about 2 inches apart. Cover and let rise for 45 minutes.
Bring water to boil in steamer or wok. Cover and steam, 2 trays at a time, for 5 minutes. Reverse trays and steam until puffed and dry to the touch, about 5 minutes.
Dipping Sauce: Meanwhile, stir together soy sauce, vinegar and sesame oil. Serve buns hot or slightly cooled with dipping sauce in small side saucers.