Pinch to seal. Place bun pleated side down on a parchment square. Repeat with remaining dough and filling. Bake 20 minutes. Makes 20 buns.
Most Chinese breads are steamed, which is why they look pale and uncooked to the Western eye.
Put the yeast and 1 tablespoon of the sugar in a small bowl. Let stand 5 minutes, then stir to dissolve. If should foam and bubble. If it does not, discard and use a fresh package of yeast. Stir in the egg, oil and remaining milk.