Prepare the pork asado filling

Heat a small saucepan Pour in the oil. Over high heat, brown the ground pork. Add the rest of the ingredients, except the water and cornstarch. Cook for 5-7 minutes, stirring often. Disperse the cornstarch in the water and pour into the pan. Cook, stirring, until the mixture is thick and almost dry. Set aside.

Prepare the siopao dough

Sprinkle the yeast and 2 tbsp. of sugar over the lukewarm water. Let stand 10 minutes, or until bubbly, without stirring. Mix together the flour, baking powder, 1/2 c. of sugar and vegetable oil. Pour the yeast mixture into the flour mixture. Mix well. The dough will be soft. Transfer to a floured board and knead with your hands, using a pushing motion, until the dough is smooth (about 10 minutes). Form into a ball.

Lightly oil a glass bowl (big enough to handle the expansion of the dough). Place the dough in the bowl and cover with a clean damp kitchen towel for 2 hours or until double in volume. Punch down once, recover with the towel and leave to rise again for another 30 minutes.

Note that the maximum volume of the dough will depend on the quality of the flour and yeast.

Divide the dough into two. Form each half into a rod by hand-rolling it on the board. Cut each rod into 8-10 pieces. Take a piece of dough and flatten it with your hands, pulling the sides to form a circle. Place a bola-bola at the center and pull up the sides and twisting at the top until the bola-bola is securely stuffed inside the dough. Do the same for the pork asado filling, using about a tablespoon of filling for each siopao. To prevent the pork asado from running down the sides of the dough, place the dough on your palm and cup your hand (as in form your hand into a scoop) before placing the pork asado at the center of the dough. Place each siopao on a piece of wax paper. Arrange on a steamer with briskly boiling water.

Steam the bola-bola siopao for 20-25 minutes. The asado siopao will only need 10-12 minutes of steaming.

Makes about 20 medium-sized siopao.