Mix the warm water, yeast and the .35oz of sugar in a bowl — let the yeast activate for a minute or two.
While the yeast is blooming, combine the flour, potato starch, salt and 1.4 oz of sugar together in the bowl of your stand mixer (fitted with the dough hook).
Add in the yeast mixture, oil and tangzhong. Mix everything for at least five minutes. If it looks like it’s not coming together, stop your machine, remove bowl and massage everything together with your hands. If it still isn’t coming together, you may need a little more water. You want a nice smooth dough with some spring to it when pushed.
Cut your dough ball in half and let it rest for 15 minutes.
Flour your countertop and roll out one half of the dough into a large rectangle, roughly 16 inches long and 8 inches wide with the long edge of the rectangle facing you.
Brush on half the sesame oil and evenly sprinkle with half the five-spice and half the green onion.
Taking the long edge that is furthest away from you, fold the top third of the dough down toward the centre, then fold the bottom third up over that. The dough will then be folded lengthwise in thirds to form a narrow rectangle that is still 16 inches long and 8 inches wide thus forming three layers.
Cut the dough in half and place one 7-8 inches piece over the other. Now your roll has six layers. Cut into six even strips — each of these will become a bun.
Press a chopstick down the length of each small rectangle. This helps stick it together and stretch it out. Now pull and twist each strip into a long rope and tie it into a knot. This step is a little tricky, but it’s made easier by having let your dough rest earlier. The buns don’t have to look perfect — the dough is very forgiving.
Repeat steps in green for the second half of your dough.
Cut some parchment paper into small squares and place each tied up bun onto a square. Cover the buns and let them proof, somewhere warm, for 45 minutes, or until almost doubled in size.
Place the buns (on their little pieces of parchment) in a bamboo steamer, but don’t crowd them. They’ll get even bigger while steaming. Most at-home bamboo steamers can hold three buns per level.
Steam for twelve minutes at medium-high heat and serve with the Miso Honey Lemon Butter on the side.
If you haven’t eaten all of them, the buns will keep nicely in the fridge for a few days. Steam again briefly, fry the bottoms in some butter until brown, and serve them with more of the butter.