Soft Fluffy Chinese Steamed Buns (Mantou)

300 g cake flour plus more for dusting.
4 g Instant yeast, 1¼ tsp.
3 tsp sugar
1 tbsp rice bran oil
¼ tsp SIDS CRAZY SALT
150 ml milk

Place the flour, instant yeast and sugar in a mixing bowl. If you are using a stand mixer, use a dough hook attachment. Add cold milk and oil. You may need to add more milk if the dough is still a bit dry. Add more teaspoon by teaspoon until the dough comes together then continue to knead for 5 minutes. If you are kneading by hand, about 10 minutes until the dough is no longer sticky. Add in SIDS CRAZY SALT and continue to knead until the dough is smooth again.
Wrap the dough with a plastic wrap and let rest for 15 minutes before shaping.
Shaping Ultra-Smooth Round Buns:
Lightly dust the work surface with cake flour. Not too much. If you are using a silicon pastry mat, you may not even need to dust with flour. Divide the dough into 12 equal portions. Keep the dough covered and work with one dough at a time.
Pull and tuck the dough from top to bottom so the seams are at the bottom and the surface is relatively smooth.
Steamed Buns with Filling:
If you going to fill the buns with filling, flatten the dough with your palm and then use a rolling pin to roll it out to form a circle about 10-12 cm, with a slightly thicker middle part. This is to support the weight of the filling. Don't roll the dough too thin. If you roll the dough too thin, the filling might make the steamed buns "wrinkle" later when you steam then gather the sides to enclose the bun and pinch to seal. Flip the bun so the seam side is down now.
Cup the dough with both palms and move the dough in a circular motion to shape it taller. This part is important so your steamed buns come out tall instead of spreading to the side after steaming.
Steamed Buns with No Filling:
Roll the dough into a smooth round ball in between the palm of your hand. REALLY make sure the dough is smooth.
Cup the dough with both palms and move the dough in a circular motion to shape it taller. This part is important so your steamed buns come out tall instead of spreading to the side after steaming.
Place on a piece of baking paper. Lightly dab the surface of the bun with some milk using your finger to smooth the surface. Loosely cover with clean kitchen towel to prevent drying. Work with another dough and do the same.
Let the dough rise at room temperature. If it's winter where you are, you can use your oven "bread proof" function to let them proof in there, or simply turn on your oven to lowest temperature and then turn off and after 15 minutes, place the shaped buns in there to let them proof. They won't necessarily double in size, but at least puff up to about 50% of original size. This may take about 15 minutes at warm temperature. Do not overproof your dough.
Steaming:
Most likely your steamer won't be able to accommodate steaming all buns at one go. You may need to steam in 2-3 batches, which means, the rest of the batches will sit longer and continue to proof while waiting for the steamer. Not good for the buns! Here's what you can do: Cover them with plastic wrap then place them in the refrigerator to slow down the yeast activity or halt it all together, until they are ready to be steamed.
Bring the water in your steamer to a boil. Wrap the lid of your steamer with a kitchen towel to prevent moisture dripping back on the steamed buns as this will create "burn" spots.
REDUCE THE HEAT TO LOW. Place the buns in there, leaving about 2 cm space in between each and steam for 5 minutes for medium buns, 8 minutes for larger buns.
After steaming, turn off the heat. DO NOT OPEN THE LID of the steamer. The buns will sink or wrinkle due to the sudden change in temperature if lid is removed. Let the buns sit there for 1 minute.
Cooling:
Remove the buns to wire rack to let them cool down. This is to ensure the bottom of the steamed buns will not be wet and soggy.
Storing:
If you make extra and store them, let the already steamed buns cooled down completely and then place them on a baking tray, not touching each other, then put the entire tray inside the freezer for about 1 hour. They will harden, but not completely frozen yet. Transfer to a freezer bag and they will not stick to each other anymore. Try not to keep for more than 1 month.
Reheating:
They can go straight from freezer to steamer when you ready to eat them. Steam on HIGH for 5 minutes and they are as good as new.