Start with 150 ml (about 2/3 cup) of milk or water (make sure it's cold or room temperature, NOT warm)plus more to dab the surface of the buns later, see note 5
Prepare the dough with a machine:
Place the all the flour, cornstarch/wheat starch, instant yeast, sugar, oil in a mixing bowl. If you are using a stand mixer, use a dough hook attachment. Add cold milk or room temperature water. If I use cake flour, I need less liquid, but if I use combination of all-purpose flour and cornstarch, I need close to 200 ml of liquid. So, start with 150 ml and add more until you can form a dough. You will most likely need to add more milk/water if the dough is still a bit dry. I would rather you start with a the lowest amount of liquid and add more teaspoon by teaspoon until the dough comes together and continue to knead for 5 minutes
Prepare the dough by hands:
Place the all the flour, cornstarch/wheat starch, instant yeast, sugar, and oil in a mixing bowl. Start with 150 ml of liquid, most likely you will need more liquid than called for in the recipe. Mix until you get a rough dough (it's not going to be smooth yet). Cover and rest it for 15 minutes. Then go back and knead it. You'll be surprised by how easier it is to knead it now. Knead until the dough is smooth and pliable, about 10-15 minutes. At any point during kneading, you can always stop and rest the dough if you find it hard to knead. This is to relax the gluten. Then go back to knead again and you'll be surprised by the difference it makes by just resting the dough before kneading again. It's easier for you too
Rest the dough (to relax the gluten, not to proof the dough):
Cover and rest the dough for 15 minutes. This is not to proof the dough. It shouldn't double in size. This is to relax the gluten for easier shaping and rolling the dough, then proceed to next step that's applicable to you
If you are going to make steamed buns with filling:
Divide the dough into 12 equal portions. Lightly dust the work surface with some flour. Work with one dough at a time. Knead the dough a few times to push out any air bubbles (if any). Flatten the dough with your palm and then use a rolling pin to roll it out to form a circle about 4-5 inches, 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. Place the filling at the center and 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. Repeat with the rest of the dough. Cover with a clean kitchen towel and proceed to proofing
If you are just making plain steamed buns with no filling (round shape):
Divide the dough into 12 equal portions. Lightly dust the work surface with some flour. Work with one dough at a time. Knead the dough a few times to push out any air bubbles (if any)
Then pull and tuck the dough so the seams are at the bottom and the surface is smooth and round. Roll the dough into a smooth round ball in between the palm of your hand or as I did in the video. 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 parchment 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. Proceed to proofing after that
For mantou shape:
Roll the dough into a long log and use a dough cutter to cut into 8 equal portions using serrated knife is best so it won't squish the dough down. Lightly dab the surface of the bun with some milk using your finger to smooth the surface. Proceed to proofing step below
Let the dough rise at room temperature or at a warm place. 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 the 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 the original size. This may take about 30 mins to 1 hour at a warm temperature. Don't go by the time however
For active dry yeast and fresh yeast, you may need a bit longer for it to proof compare to instant yeast. If you use more sugar in the recipe, you may need to proof a bit longer too. Do not overproof your dough however
How do you know if your buns have proofed ? They will be about 50% bigger than their original size AND when you lift them up, they should feel lighter. If not, let them proof a bit longer. They won't visually look bigger. Use a finger test too. When you gently push on the dough, it will leave an indentation but it will spring back slowly. This dough is perfectly proofed. If it springs back right away, it needs to be proofed a bit longer. If it never springs back, then you have over proofed the dough. Loosely cover them with a plastic wrap and put the overproofed buns in the fridge to slow down the proofing while waiting for the steamer
Most likely your steamer won't be able to accommodate steaming all buns at one go, unless you have something like this 3-tier food steamer (which I really love). 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: Make sure to cover them with plastic wrap and 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
LOWER THE HEAT TO MEDIUM. Place the buns in there, leaving about 1-inch space in between. Cover with a lid but leaving it about 1/4-inch gap for some steam to escape. Steam on medium heat for 15 minutes for plain medium-large buns with no filling, 20 minutes for large buns with raw meat filling. This is especially important if you see that you have overproof the steamed buns (the steamed buns have doubled in size and they have widened to the side). As long as you steam them like this, the buns will not wrinkle and collapse later when you take them out from the steamer
After steaming, turn off the heat. DO NOT OPEN THE LID of the steamer. Let the buns sit there for 5 minutes or longer like this. The buns will not sink or wrinkle due to the sudden change in temperature
Immediately 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
If you make extra and plan to store them, let the already steamed buns cooled down completely and then place them on a baking sheet, not touching each other, and 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
They can go straight from freezer to steamer when you ready to eat them. Steam on high heat for 5 minutes and they are as good as new
You can use active dry yeast, but make sure to rehydrate the yeast in water or milk with 1 tsp of sugar. It will dissolve and be all foamy, about 10 minutes. If it's not, your yeast is no longer good. You can add the rest of the sugar into the dough later
You can also use fresh yeast, the amount would be 4 x the amount of instant yeast. So you'll need 16 grams of fresh yeast
I highly recommend testing the yeast for activity before starting to work on this recipe. You don't want to wait for hours only to find out your yeast is no longer good. Here's how: Add 1 teaspoon of sugar and 2 1/4 teaspoons of yeast (one envelope) to 1/4 cup of warm water. Wait for 10 minutes and if you see foams and bubbles and you smell that yeast aroma, your yeast is still good to go. If not, then you need to get fresh yeast.
You can also replace all 300 gr of all-purpose flour and 60 gr cornstarch/wheat starch with 360 gr of cake flour or premixed Hongkong/Vietnamese bao flour and omit the wheat starch/corn starch.
I recommend to start with small amount of liquid and add more as you go because it really depends on the type of flour you use (they absorb liquid differently) and that's why I can't give you an exact amount but 150 ml is a good start and add as you go.