This legendary Asian street food isn't as hard to make as you might imagine. Add chili paste to the marinade if you want to add a kick. Feel free to substitute the vegetables as desired to make your own unique pork buns!
1. Trim fat from the pork, and cut pork into strips.
2. Create a marinade using all ingredients except for the meat and vegetables. Thoroughly coat the pork in the marinade, and refrigerate in a sealed container for at least an hour.
3. Add yeast, sugar, and warm water to a mixing bowl. Allow to proof until foamy, about 5 minutes.
4. Using a mixer equipped with dough hooks, gradually blend the flour, cornstarch, and salt into the yeast mixture on low speed. Continue blending until mixture looks shaggy in appearance.
5. Knead dough by hand until there are no dry spots. Spray inside of mixing bowl with cooking spray and roll the dough to coat. Cover with plastic wrap and allow to rest in a warm place until doubled in size, about an hour.
6. While the dough is rising, heat a pan to mediunm-high, and cook marinaded pork for a few minutes, reserving some of the marinade from the container. Pork will contunue to cook in remaining steps, so don't worry about doneness.
7. Add chopped vegetables and the rest of the marinade to the pan, and heat while stirring thoroughly.
8. Remove pork and vegetables from pan and allow to cool in refrigerator while preparing the dough.
9. Divide the dough into 8 equal pieces, and roll each into a ball. As you roll out each ball, cover the remaining dough to keep it from drying out.
10. Flatten one dough ball into a disc that's about 5 inches across. Add 1/8 of the pork and vegetable mixture to the middle of the disc. Pull up the edges of the disc in a fan-fold pattern as you close up the filling. Pinch together the dough to there are no openings.
11. If using a rice cooker, place a square of parchment paper to cover the holes. Arrange the pork buns, seam-side down, in the steamer so there's an inch of space between them. They will expand in the steamer, so this will avoid them sticking together.
12. Steam pork buns for 10 minutes, or until the dough seems to be set. Remove pork buns from steamer by inverting the steamer onto a plate: removing them individually can cause parts of the surface to break, since the dough will still be somewhat sticky. Repeat for remaining pork buns.
13. Refrigerate pork puns with a layer of parchment paper between them so they don't stick together.