Step 1

Beat sugar, yeast, baking powder, and 1¾ cups (250 g) Hong Kong flour or cake flour in the bowl of a stand mixer fitted with the dough hook on low speed to combine. Combine milk, cream, and ¼ cup water in a measuring glass or small bowl. Reduce speed to low and, with motor running, gradually pour in milk mixture and mix until dough forms a ball, about 2 minutes. If dough has not formed a ball by then, gradually add more flour a teaspoonful at a time until it does. Continue to mix until very smooth, about 8 minutes more. (Alternatively, you can mix in a medium bowl with a wooden spoon or your hands until a shaggy, loose dough forms, then turn out onto a clean surface and knead until smooth and glossy, about 10 minutes. Place in a large bowl to rise.) Remove bowl from mixer and cover with a damp kitchen towel. Let dough rest until slightly puffed, 30–60 minutes.

Step 2

Meanwhile, cut out thirteen 3"-squares of parchment paper.

Step 3

Portion dough into 13 equal-size pieces (use a scale if desired). Roll each into an 8"-long rope. Tie each rope into a knot and tuck the end that came through the knot underneath the bun. Tuck the other end up and over the top. Place buns on parchment squares as you go.

Step 4

Cover buns loosely with damp kitchen towel and let rise in a warm place until slightly puffed and marshmallow-y in texture, 30–45 minutes.

Step 5

Pour water in a wok or large pot to come 1"–2" up sides. Set a steamer with a lid over wok, leaving at least ½" of space between the inside layer of steamer and water. Bring water to a boil over medium-high heat.

Step 6

Place as many buns as will fit in steamer, spacing about 2" apart. Cover and steam until cooked through, about 8 minutes. Transfer mantou to a plate. Repeat process with remaining buns, adding more water to wok as needed. Serve warm.Do ahead: Mantou can be steamed 2 months ahead. Freeze on a baking sheet until solid, then transfer to resealable plastic freezer bags or airtight containers and keep frozen. To serve, thaw in refrigerator overnight, then re-steam 3 minutes.