[Image: Three cha siu bao in a steamer basket — soft, white, fluffy, slightly sweet steamed buns filled with barbecued pork. The tops of the buns are "smiling" to show the filling.]
Cha siu bao (叉燒包/chā shāo bāo) are probably familiar to most people who've ever been out for dim sum. I'd been intending to cover them during this year's dim sum month (which will again be in August), but since this week's character post was on 包/bāo/bun, they were the obvious choice for today's post.
I didn't want to get too complicated for my first attempt at these, so I decided to buy the 叉燒 instead of making it myself[see footnote]. Many Cantonese restaurants will sell you a chunk of cha siu to take away, at a reasonable price; it's best to go around lunchtime, as it's fresher then. Look for somewhere that has roast meats hanging up in the window, and ask to have your cha siu whole rather than cut up, so it doesn't dry out on the way home. If you do want to make your own, check out sung's cha siu recipe.
To turn my purchased chunk of 叉燒 into 包 filling, I followed Sue-On's instructions to dice it and then stirfry it with hoisin sauce and oyster sauce, before adding chicken stock and thickening it with cornflour slurry (the Tigers & Strawberries post linked below has a more complex recipe). I have to confess that, not being the greatest fan of 叉燒包, I hadn't eaten one in recent memory, so I wasn't entirely sure what flavour I was going for here. Instead, I aimed to get a decent amount of sauce that was thick enough to be folded up in a dough wrapper without leaking everywhere, but that wasn't too stodgy. I did make one mistake, in that I didn't dice the meat quite finely enough. I left this filling to cool completely before filling my buns.
The other important component is the bread dough. There are two main schools of thought on this: yeast-raised, or non-yeast-raised, though many yeast-raised doughs, such as the one from Tigers & Strawberries, also incorporate some baking powder for extra lift. There's another yeast-raised dough posted by Tepee on eGullet; note though that I haven't tried either of these yet, since I decided to go for a non-yeast option.
Non-yeast-raised doughs might use baking powder or ammonium bicarbonate as the raising agent. Some are kneaded and then left for 20-30 minutes to relax the gluten, while others are used straight away. Some people use water for the liquid, others use milk.
In the end, I tried two ways of making the dough; the boxed mix described below, and the dough recipe from Sue-On's bao page linked above. Sadly the latter simply didn't work for me — I thought all along that the proportions looked off, so I measured carefully and followed the instructions to the letter, but even using the most generous conversion I could find (1 cup flour = 5 oz weight), I still ended up with a batter rather than a dough, so I chucked it in the bin and had toast instead.
The boxed mix was a serendipitous discovery. I read online that Vietnamese "banh bao flour" was a good flour to use, so I went to our local Vietnamese supermarket and asked for some. The owner pointed me at a box of Thai "salapao mix" (photo of salapao mix box), which contained flour, sugar, and raising agents. I thought this was worth a go, so I bought some. The dough turned out quite soft, which surprised me, since according to the Tigers & Strawberries recipe linked above, the dough should be stiff, but I figured this was probably just a difference between the yeast-raised and non-yeast-raised versions, and indeed it was fine in the end.
Most recipes ask you to form the dough into a roll and then cut it into however many pieces it's meant to make — I prefer to weigh it, work out how much each one should weigh, and then pull off pieces and check the weight, but then I like doing long division, so just use whatever method suits you :) Sue-On's post, linked above, mentions using a tortilla press to make the flat circles, but I just rolled them out with a rolling pin.
For steaming, it's best to use a steamer with a bamboo lid, since it absorbs the condensation better than a metal lid does, and you don't really want condensation dropping back onto your 包. Note that they do get quite a lot bigger when you steam them, so make sure to leave plenty of room between them when you put them in the steamer.
To stop the 包 sticking to the base of the steamer, I used these circles of parchment paper stuff that I bought from the Chinese supermarket; they're cut to a standard size, and they have holes in them to let the steam through. They worked very well, no sticking at all. I've read that you can also use lettuce leaves, though these can make the bases of the 包 a bit soggy; I've also read that if you don't mind having to peel the paper off the buns afterwards, waxed paper works OK.
A number of sources on the internet suggest that adding some white vinegar to the steaming water will eliminate any "off" colours or smells, but I have no idea if this is true, nor what the mechanism might be. Similarly, many sources state that the 包 should be steamed over as high as heat as possible to get them really fluffy and to get the characteristic "cracked" or "smiling" top — I certainly noticed that the ones in the lower tier of my steamer (i.e. closer to the fresh steam) were smiling more than the ones in the upper tier. Finally, according to Tepee on eGullet, you should avoid overcooking (12-15 minutes is a good time), and uncover your 包 as quickly as possible once they've finished steaming, making sure not to let any condensation fall on them.
If you have leftover 包, let them cool down, then freeze them. Reheat by steaming from frozen for 10-15 minutes.
Footnote:  Since I was planning to be in central London anyway, I googled for where to buy cha siu in london chinatown and was amused to see a post by sung come up as the top hit. In his post, he recommended Hung's on Wardour Street, so I decided to go there, but was thwarted by an earlier appointment over-running; however, we met up for dinner the next evening so I got to wander along Gerrard Street with him afterwards peering in all the windows to select the best-looking cha siu for me!