Add the milk, yeast, and sugar to the bowl of a stand mixer fitted with a dough hook. Stir the mixture with chopsticks or a spoon.
Add the flour to the yeast mixture. Turn the mixer to speed 1 and knead the ingredients until a smooth dough forms, about 6 minutes. If the dough starts to ‘climb up’ the dough hook, stop the mixer and push the dough back down into the bowl.
Transfer the dough out, cover it with plastic wrap, and let it rest for 5 minutes.
On a lightly floured surface, roll out the dough with a rolling pin from bottom to top. Turn the dough horizontally and roll again from bottom to top. Continue rolling the dough until it forms a 14×10″ (35cm x 25cm) rectangle.
Roll up the dough into a log from left to right. Make sure to tuck and roll the dough tightly to form a compact log.
Roll out the log a few times until the surface looks smooth and it reaches 12 inches (30 cm) in length.
Cut the dough into 8 equal-sized pieces using a sharp knife. Transfer each piece to a 3×4-inch (7 cm x 10 cm) piece of parchment paper. You may roll each piece into a round ball after cutting.
Place the dough into a steamer. Cover the steamer and let the dough rise for 60 minutes, or until the dough balls expand in size. Make sure to leave enough space between each dough ball so they don’t stick together.
Add water to the bottom of the steamer. You may add 1 teaspoon of Chinese white vinegar to make the steamed buns whiter. Cover the lid tightly
Turn on high heat and steam for 10-12 minutes, or until the dough expands into soft, puffy, and fluffy steamed buns. Turn off the heat and serve the steamed buns warm. Dip in condensed milk if you like sweet steamed buns.