Steamed Char Siu Bao (Chinese BBQ Pork Buns)

Cook the BBQ pork filling:

1. In a large frying pan, sauté the onions and garlic until translucent, about 3-4 minutes over medium heat.
2. Add in the diced BBQ pork and continue to sauté until the pork is heated through. 
3. Next, add in 5-spice powder, Chinese rose wine, hoisin sauce, and ketchup.
4. Prepare the cornstarch and flour slurry by adding 1 teaspoon cornstarch and 1 teaspoon flour into a small bowl with 4-6 tablespoon cold water. Mix with a spoon until the starch and flour dissolves.
5. Pour the cornstarch slurry into the pot and stir to coat the BBQ pork mixture. Bring to a boil and lower the heat.
6. The mixture will begin to thicken and become glossy.
7. Remove the BBQ pork filling from heat, stir in a little sesame oil, and transfer to a clean bowl. Cover with a lid and let cool.
8. Refrigerate the pork filling for at least 4-6 hours, or overnight.
9. Use a small ice cream scoop to divide the BBQ pork mixture into 10 portions, about 25-30g each.
10. Place the scoops onto a plate and chill in the fridge until just about ready to assemble. (Don't keep it at room temperature).

Make the starter: (the night before)

1. In a small bowl, add in 113g cake flour, 2g of active dry yeast, 15g of sugar and 62g water.
2. Knead together until it forms a dough. (It will be on the drier side).
3. Cover with plastic wrap and leave at room temperature overnight.

Make the dough:

1. Transfer the starter mixture from the night before in to a larger bowl.
2. Add 2g baking ammonia dissolved in 2 teaspoon of water + a few drops of lye water. (Be careful, it will smell!)
3. Knead in the 60g granulated sugar, until it dissolves a little.
4. Add in the cake flour, wheat starch and baking powder.
5. Add in the milk, coconut oil, and vinegar.
6. Knead until the dough comes together.
7. Cover the bowl with a plate or plastic wrap and leave it to rest for about 30 minutes in a warm location.
8. When the dough shows some bubbles and has risen a little, lightly dust the work surface with some wheat starch and divide the dough into 10 equal portions. (About 45-50g each).
9. Roll the portioned dough into a flat disc and place a scoop of char siu BBQ pork filling (about 25-30g) in the centre.
10. Gather the dough up in 3 places, forming a triangular shape (like a samosa).
11. Gently press the centre down, and gather the sides up, forming a "bulb/tulip."
12. Pinch the 3 seams together on the sides.
13. Place the bun onto a piece of parchment paper or muffin liner.
14. Repeat with the remaining dough and filling.
15. Cover the buns with some plastic wrap and leave to rest in a warm location for about 20-30 minutes.

Steam the buns:

1. Fill a large wok or pot (that can fit a steaming rack) with water and add 1 tablespoon white vinegar to it.
2. Bring the water to a boil over high heat.
3. Once the water is vigorously boiling, place 3-4 buns onto the steaming rack and transfer it to the pot or wok.
4. Cover with a lid and ensure that any steam vents are covered (I used a wet cloth), and place a kitchen towel over the rim of the lid, to help trap in as much steam.
5. Steam the buns for 12-13 minutes, until buns have formed cracks.
6. Remove the buns and repeat with the remaining buns.
7. The buns are best served immediately, hot and steamy.