Cut up the parchment paper into 24 squares about 10 cm / 3 inches square.
Proof the yeast in a bowl or cup in the 1/4 cup of warm water with a pinch of sugar added, until foamy.
In a large bowl, put in 5 cups of the flour. Make a well in the center, and add the hot water and mix rapidly.
Add the sugar and yeast/water mixture, baking powder, warm milk, and the shortening or lard. Mix well.
Add the rest of the flour little by little until you have a workable dough. Knead for a few minutes on a floured board until it's soft and pliable.
Put into a large bowl, cover with a clean towel, and leave in a warm place until the dough has doubled in bulk, about 45 minutes.
Take out the dough and roll into one long sausage. Cut the dough into 24 pieces. Roll each piece into a ball, and let rest for a bit.
To fill the buns, flatten each ball so that the middle is slightly thicker than the edges. Put about a tablespoon or so of filling in the middle. Gather up the edges and pinch them firmly together to seal, then turn the bun over and place on a square of parchment paper. Let the buns rise for 15-20 minutes before steaming.
Steam in a steamer for 20 minutes. Eat while piping hot.
Soak the shiitake mushrooms in warm water until soft. Cut off the hard stems and slice thinly.
Cube the pork, or chop it up finely.
Mix the flour and cornstarch with the water.
In a pan heat the sesame oil and toss in all the ingredients except the flour/cornstarch water. Sauté briefly, then add the flour/cornstarch water. Cook until it's a bit syrupy.
Let cool and use to fill the buns.
The Chinese-style roast pork (Chinese: char siu; Japanese: yakibuta).
If you have a big piece of pork, cut it into about 500g pieces.
Roughly chop the ginger, skin on is okay, and crush the garlic to crush a bit.
Put the pork pieces in a sturdy plastic bag or container. Put in the pork, ginger, star anise and garlic, and fill with enough soy sauce to cover the pork.
Seal the bag well and marinate in the refrigerator overnight. Turn the meat several times if you can so that the marinade penetrates evenly.
Preheat the oven to 140° C / 280°F
Empty out the contents of the bag into a baking dish. Add a bit of water so that the meat is sitting in about 1cm of liquid.
Sprinkle the meat with sugar, and bake for about 2.5 - 3 hours, turning the meat every 20-30 minutes. If you want it even sweeter, sprinkle more sugar on the meat periodically.
At the end, the liquid will be almost gone and syrupy, and you will have dark amber colored pieces of pork.
Let cool and slice thin, cube, etc. You can use cubes in fried rice, or in the steamed buns of course, and any number of things.
It is quite worthwhile to make this in some quantity, since the cooking takes so long, and to freeze in portions for later use.