Bao Buns

Preparation

1. Step 1

   Place milk in a small saucepan and heat over low until it reaches 95 to 105 degrees. Whisk the flour, yeast, sugar, baking powder and salt in the bowl of a stand mixer fitted with the dough hook. Drizzle in half of the warm milk and mix with a rubber spatula until combined. Add the remaining milk, and mix again with the spatula until well combined. The dough will be dry and shaggy.

2. Step 2

   Turn the stand mixer on low; knead with the dough hook until a smooth ball has formed, about 5 minutes. At first, the dough will be dry, but as the kneading continues, it will become slightly tacky. Remove the bowl from the stand mixer base and cover with plastic wrap. Let the dough rest for 15 minutes on the counter in a warm place. (Alternatively, if hand kneading, mix the ingredients in a large bowl until combined, then transfer to a clean surface and knead until a smooth ball is formed, about 10 minutes. Cover before resting.)

3. Step 3

   Lightly brush a large glass bowl with 2 teaspoons of oil and set aside. After the dough has rested, return the bowl of dough to the base of the stand mixer and knead on medium speed until it feels smooth, about 5 minutes. (If hand kneading, transfer the dough to a very lightly floured surface. Knead until the dough is smooth without any dry bits of flour, about 10 minutes.) Place the dough in the greased bowl, cover with plastic wrap and let rise in a warm place on the counter until doubled in size, 45 minutes to 1 hour (see Tip 1).

4. Step 4

   Punch down the dough and transfer to a very lightly floured surface. Divide the dough in half and cover one half with a clean dish towel. Divide the other half into 8 pieces, rolling each into small balls. Lightly flour a rolling pin, roll each ball into a 6-by-3½-inch oval. Lightly brush the side facing up with oil and fold into half, creating a semi-circle. Transfer dough to a parchment-lined baking sheet, placing the semi-circles about ½ inch apart, and cover with a clean dish towel as you continue forming them. Repeat with the remaining half of the dough. Cover the baking sheet with plastic wrap and let rise until doubled in size, about 15 minutes.

5. Step 5

   Meanwhile, set up a steamer station: Bring a large wide pot or wok filled with 2 inches of water to a rolling boil. (The pot should be wide enough to fit a 10- or 12-inch bamboo steamer or steamer basket without touching the boiling water.) Line each layer of the bamboo steamer or the base of the steamer basket with perforated parchment to prevent the bao from sticking (see Tip 2). If using a lid other than the bamboo steamer, wrap it with a clean dish towel to soak up the condensation while steaming.

6. Step 6

   After the dough has risen a second time, transfer to the steamer in an even layer at least 1 inch apart. Depending on the size of the steamer basket, you may need to do this in a few batches. Cover and steam on high heat for 5 minutes. With the lid on, let the baos rest off the heat for 3 minutes, then remove to a plate and cool slightly before filling.