Makes about 40 dumplings. The soup gelatin recipe is enough to make 2 batches (80 dumplings total). You can freeze leftover gelatin for the next time you make Xiao Long Bao. Or double the dumpling filling and wrapper recipe to make a total of 80 dumplings.
In a large stockpot, place all of the ingredients EXCEPT the gelatin/agar agar. Bring to boil, reduce heat and simmer for 45 minutes, uncovered. Use fine meshed strainer to remove the scum on surface. Taste, and adjust with salt, if needed. The ham is salty, so you might not need additional salt.
Measure out 4 cups of the broth (you'll only use 4 cups of broth...reserve any leftover to use in future soups) and pour into a medium saucepan and bring to a almost a boil.
Turn heat off and stir in the gelatin or agar agar. Whisk until all powder is dissolved. Pour broth into an 8x8 baking dish (size really doesn't matter. if you have a few plastic containers, use those instead. remember how you used to make jello?) Refrigerate until set, about 3-4 hours. (I stuck mine in the freezer after the first hour because I got impatient...it only took 2 hours for mine to set)
When the gelatin is set, use a fork to criss-cross the gelatin to break into very small, 1/4" pieces. Alternatively, you can carefully cut into small cubes. Reserve about 1 1/2 cups of the soup gelatin. Freeze any remainder for future use.
In a large bowl, combine and mix all of the ingredients, including the 1 1/2 cups of soup gelatin. Stir to incorporate gelatin evenly throughout. Refrigerate until ready to use.
Put about 90% of the flour in a large bowl. Pour about a third of the hot water in the flour. Use a wooden spoon to stir vigorously. Add more hot water. Stir more. Add the last bit of the water and stir vigorously until the dough begins to form. Add all of the cold water and oil. Keep stirring vigorously. Stop when you can't stir anymore.
Dust counter with the remainder 10% of flour. Place dough on floured surface, use your hands to knead the dough for 8 -10 minutes, until it becomes soft, smooth and bounces back slowly when poked with your finger. Cover with plastic wrap and let it sit for 30 minutes.
Divide the dough into 4 equal pieces. Take one piece (cover the remaining 3 pieces with plastic wrap) and roll it into a long log, about 1-1/4" diameter. Using pastry scraper or knife, cut dough into 10 pieces. Work one dough ball at a time, keep the remaining covered with plastic wrap.
Roll one of the balls between your palms to get a nice, round, smooth ball. Using a rolling pin, roll it out flat to about 3" round. OPTIONAL: Roll dough to slightly larger than 3" round, then use 3" round cookie cutter to create a nice, even circle. No cookie cutter? improvise with empty tin can.
**Note, you may need more flour as your are rolling out your dough. I always keep the counter dusted and a small pile of flour nearby so I can quickly nudge some over if I need it.
Fill with 1 tablespoon of filling, pinch pleat all the way around. Repeat with rest. Make sure that you cover any dough that you aren't currently using and cover the dumplings with a towel to prevent drying.
Whisk together the ingredients in a bowl with the ginger. Serve with Xiao Long Bao dumplings.
Separate the leaves of Napa cabbage. Cut away and discard the tough, thick stem that curves up.
Nutrition values are for each dumpling.