Siopao Filling

1. Using a fork, shred the mushrooms. Refer to this video to learn how. 
2. In a large pan or skillet over medium heat, add oil. Once heated, add the onions and garlic, and cook until the garlic is fragrant and the onions are translucent for about 3-4 minutes.
3. Add the mushrooms and cook for 2 minutes, mixing often.
4. Pour in the oyster sauce, hoisin sauce, soy sauce, granulated sugar. Mix everything until uniform.
5. In a small bowl, mix the cornstarch and warm broth until uniform. Add the cornstarch mixture to the pan and a pinch of black pepper and mix until everything is uniform.
6. Allow the mixture to cook until the sauce thickens, about 8-10 minutes. Taste and adjust flavor as needed. Set aside and cool completely.

Siopao Dough

1. To a small bowl, add in the warm water and 1 tablespoon of sugar. Mix well. Add in the yeast and mix. Allow it to sit for 10 to 15 minutes.
2. In a large mixing bowl, add the remaining 1/4 cup of sugar, flour, baking powder, and salt. Mix well.
3. Add the shortening and work it in with a fork until it becomes a sand-like consistency and is evenly distributed throughout the dry mixture.
4. Add the yeast mixture into the flour mixture and mix it with a spatula until smooth. Transfer the dough to a floured surface and knead until smooth, adding more flour to water, 1 tablespoon at a time as needed.
5. Transfer to a greased bowl and cover with a damp clean kitchen towel or oiled plastic wrap. Place it in a warm area to rise for 1 to 2 hours, or until doubled in size.
6. Punch down the dough and divide it into 10 equal portions. You can use a scale to ensure they are all even. Form each piece into a ball and arrange it on a baking sheet in a single layer. Cover them with a wet towel or oiled plastic wrap as you work. Rest for 10 minutes.
7. Using a rolling pin or a flat-sided cup/bottle, out the dough into a 3-inch circle. Then, continue rolling out only the edges until about 5-6 inches.
8. Add 1 tablespoon of filling into the middle of the circle and wrap. Be sure to keep the filling away from the edges. I do this by folding in the right and left flaps, holding that together, and bringing in the top and bottom. Then I fold each flap in half in the middle to form 8 pleats, then twist it all together to seal. Place a piece of parchment paper underneath and place it back onto the baking sheet. This might be tricky at first, but you will get the hang of it. Refer to this video for more instruction. You can also tightly seal the dough and flip it over so that the crease is on the bottom and the smooth side is on top. Rest covered in a damp towel or oiled plastic wrap for 10 minutes.
9. In the meantime, prepare your steamer. Prepare a steamer with water and 1 tablespoon of white vinegar. Be sure the water does not touch the bottom of the steamer or your siopao will be soggy. Bring the water to a boil and set aside, covered.
10. Place the buns in the prepared steamer at least 1-inch apart (they expand a lot) and steam on low for 15-20 minutes. If you are preparing this in 2 batches, place the extra in the fridge to not overproof. This all depends on the steamer and the water. Remove from heat and allow the buns to sit in the steamer (still closed) for 5 more minutes to prevent it from collapsing. Uncover and serve with the sauce. Enjoy!

Siopao Sauce

1. In a medium saucepan, add the broth and bring it to a boil.
2. Add everything except the water, cornstarch, salt, cover, and simmer for 10 minutes.
3. Remove from heat and then strain the mixture through a fine-mesh kitchen strainer into a large bowl, being sure to press all of the liquid out of the “pulp.”
4. Transfer the liquid to a clean saucepan and bring to a boil.
5. Mix the water and cornstarch in a small bowl, then add in this diluted cornstarch mixture. Stir continuously until thick. Taste and add salt if needed.
6. Remove from heat and cool.