Chinatown baked pork buns (char siu bao)

Instructions

1. To make the tanzhong dough, place the extra 2 tablespoons of flour and ½ cup (125 ml) of water in a small saucepan over medium heat. Cook, whisking, for 2 minutes, or until thickened to a paste (tanzhong). Transfer to a bowl to cool.
2. Place the remaining flour, the sugar, yeast, and salt in the bowl of a stand mixer fitted with a dough hook. Whisk to combine. Add the milk, egg, and tanzhong and knead for 3 minutes, or until the dough comes together. Add the butter, one piece at a time, kneading until combined, then knead for a further 8 minutes, or until the dough is smooth and elastic (it will be quite sticky).
3. Transfer the dough to a greased bowl, then cover and stand for 1 hour, or until doubled in size. (You can also make the dough ahead of time and refrigerate after it’s proved — which also makes it less sticky when rolling.)
4. To make the filling, heat the vegetable oil in a saucepan over medium heat. Cook the onion, stirring, for 3 minutes, or until softened. Add the pork, oyster sauce, soy sauce, sugar, sesame oil, cornstarch mixture, and ¼ cup (60 ml) of water. Cook, stirring, for 5 minutes, or until the sauce has thickened. Remove from the heat and allow to cool.
5. Line two baking trays with baking paper. Turn the dough out onto a lightly floured work surface and divide into 16 even pieces. Roll each piece into a ball, then flatten to a 10 cm round, using your fingers to make the rounds thinner at the edges (this ensures an even amount of bread at the top and bottom of the bun).
6. Place a scant tablespoon of the filling in the centre of one dough round, then pull the edges of the dough up and around the filling to enclose, pinching or twisting the dough to seal. Place the bun, seam side down, on one of the prepared trays, then repeat with the remaining dough and filling. Cover the buns with greased plastic wrap and set aside in a warm place for 30 minutes.
7. Preheat the oven to 180ºC.
8. Brush the buns with the beaten egg, then transfer one tray to the oven and bake the buns for 15 minutes, or until golden. Transfer to a wire rack to cool, then repeat with the remaining buns. Serve warm, or at room temperature.