Snowskin Mooncakes

by Xinyu on 05th Oct, 2013

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We made mooncakes for Mid-Autumn Festival this year once again. Since our previous attempts at the more traditional kinds of mooncakes turned out merely decent and not overwhelmingly successful, this time round we decided to try snowskin mooncakes instead.

Snowskin mooncakes (冰皮) are mooncakes where the usual baked outer crust is substituted by a sweet "skin" made out of mostly rice flour. This skin is unbaked, and (if you don't add any food colouring) is a pure white, hence giving it the name "snowskin". Because baking isn't required, they're easier to make than traditional baked mooncakes. In fact I made them once before; a long time ago back when I was in Junior College, with my then-classmates right before the Mid Autumn Festival celebrations.

We made two different types of filling; one a traditional tao sar (豆沙, red bean paste) with crushed peanuts, and the other a modern chocolate ganache with hazelnuts. I was in charge of making the tao sar while Ai Qi worked on the ganache.

Making tao sar follows the standard formula for making all kinds of Chinese sweet pastes: cook an ingredient till its soft, mash it into a puree, and then fry the puree in oil till fragrant. We've made tao sar before, as a filling for read bean buns; the recipe I'm giving here is a refinement of that one.

The first step is usually to soak the beans overnight before use. However its generally fine to just use unsoaked beans and compenstate by cooking a bit longer, as I did. I pressure cooked the red beans to save some time, with just enough water and some pandan leaves.

After about 20 minutes in the pressure cooker, the beans were done, and soft enough to easily crush between two fingers. I then mashed the beans using the latest addition to our collection of kitchen gadgets: a food mill.

A food mill is sort of like the larger cousin of a potato ricer. As you turn the handle, the stuff in the mill gets squeezed in between the metal blade and the peforated base, which forces the food out of the mill through the tiny holes. This lets you get a really smooth puree, and in effect combines the process of mashing and sieving together.

However, it took longer than I expected to mash all the beans through the food mill, and required some amount of manual effort as well. Still, it was easier than trying to force the beans through a sieve. Alternatively, if you have a good food processor or blender, you could use that instead. I don't trust the ones we have to get a perfectly smooth paste; there always ends up being a few missed chunks here and there.

The final step is to fry the puree in oil to get a paste. Generally these pastes are quite oily, so its fine to use a fair bit. We did notice that oil started seeping out of our tao sar after it was done, which might mean that I had added a bit too much. Nevertheless, you can always drain away any excess. Rather that than add too little oil, which will result in too dry a paste.

A sweetener must also be added during the frying process. I used golden syrup this year, instead of sugar. Previously, I had problems integrating the melted sugar / caramel with the puree; when the puree was added to the hot oil and sugar, the temperature would drop and the sugar would harden. Using golden syrup avoids this issue, and the flavour of the syrup works well with the red beans. I'd imagine that traditionally maltose (麦芽糖) is used, but I didn't have any maltose handy.

I also added a pinch of salt to help bring out the flavours.

I fried the tao sar till it darkened into a glossy black paste. If you've eaten tao sar before, you know what it should look like; if you don't think its really there yet, keep on frying! The frying process is particularly important and is what differentiates the Chinese tao sar from Japanese adzuki bean paste; it imparts a smoother texture, a richer mouth-feel (due to the oil), notes of caramel and a hint of bitterness. Frying also removes most of the moisture from the paste, which intensifies the flavour. It's due to this frying step that the amount of water you use to boil the beans initially doesn't really matter; all that water will eventually boil away.

The end result was a really good tao sar, one of the best I've made. I attribute it to the food mill and the use of golden syrup.

While I was working on the tao sar, Ai Qi breezily put together her ganache. She's made chocolate ganache many times before, as its a common component in many of her baking recipes. She could probably do it blind-folded and one-handed. She decided to add a shot of kahlua (coffee liqueur) to intensify the flavour of the chocolate and give it a slight alcoholic bitterness. Once the ganache was done, she left it to cool off and then proceeded to work on the mooncake skins.

We found many different recipes for snowskin mooncakes online, all quite alike. They used similar ratios of cooked glutinous rice flour (also known as koh fun or 烤粉), icing sugar and shortening. We tried making a test batch using one of the recipes, but the dough turned out far too difficult to work with. It was extremely elastic yet very brittle, so it was hard to roll out, and then tore too easily. As a result, we spent some time modifying the recipe to try to get a dough that would work better.

A Word About Koh Fun

Koh fun is a flour made from glutinous rice that has been treated by heating. Traditionally the flour is cooked by dry-frying it in a wok. I tried to find out a bit more of the science behind this process, but failed to unearth anything useful.

Adding water to koh fun forms an interesting kind of dough. It is not very sticky, but very elastic and springy. The heating process probably modifies the starches in some way to yield such a texture. The flavour of the dough is also different, reminiscent of cooked rice. It is exactly the right flavour and texture you'd want in snowskin.

However, it was probably the lack of stickiness that caused our pure koh fun dough to tear so easily; the dough did not bind together very well. Adding uncooked glutinous rice flour helps counter this, as it produces a far more sticky dough.

So why are the other recipes online using 100% koh fun in their doughs then? I suspect the koh fun we bought might have been cooked longer, thus causing it to be particularly elastic and non-sticky. So keep that in mind if you make your own mooncakes, and adjust the ratio accordingly, using more koh fun if you can.

The final recipe we derived for the skin used a 1:1 ratio of koh fun and glutinous rice flour, which just sticky enough to roll out and shape easily. It turned out pretty well, but there is still some room for improvement. I'd like the dough to be a little more stretchy, which might mean adding some wheat flour to introduce gluten. Additionally, a key component of the current recipe is icing sugar, which is really sugar with cornstartch. I'd like to replace the icing sugar with ultrafine sugar and perhaps glutinous rice flour, to get rid of that starchy flavour. Maybe next year!

Once we were done with the fillings and the snowskin dough, it was time to assemble the actual mooncakes. This is a process that takes a bit of practice; our first few attempts didn't turn out very well, but eventually we got the hang of it.

The first thing you do is shape the filling into a ball. At this point we also added the peanuts or hazelnuts.

Once that's done, you have to roll out the snowskin dough. We pinched a bit of the dough and first shaped it into a ball, before flattening it to make a circular disc. We found that sandwiching the snowskin between cling wrap before flattening helped prevent it from sticking. Keeping the cling wrap there, we then used a rolling pin to roll the snowskin out as thinly as we dared, keeping it circular.

The next step is to place a ball of filling onto the disc of snowskin, and then wrap the snowskin around the filling to form a tight seal. This is the trickest part of the process, as the snowskin disc can be pretty delicate. Eventually we settled on a technique where we wrapped the snowskin through the cling wrap. This prevents the snowskin from sticking to your fingers and tearing. Its a bit hard to describe but the picture below should give you an idea.

You'll also need to carefully pinch off some of the excess snowskin once the filling is wrapped; again, the snowskin will tear if you're not careful.

Finally, the ball of filling and skin can be put into the mooncake mould and pressed into a finished mooncake. This part is easy, as long as you did a good job wrapping the filling. We found that putting the smooth side of the ball into the base of the mould (where the prints are) resulted in a nicer looking mooncake.

One note about the chocolate mooncakes: they turned out to be really hard to wrap! The ganache melted quite easily, especially upon contact with our warm hands. Once the chocolate begins to run, it gets everywhere, and it becomes very hard to seal the skin. A possible fix for this is to work in a cooler environment (we don't have air conditioning in our kitchen) and wear some insulating gloves to prevent our hands from melting the chocolate. Alternatively, it might be possible to shape the ganache into balls and then freeze them before wrapping. Again, this is something we'll figure out for a future article.

In the end, we churned out around twenty or so mini mooncakes, and gave them to relatives and friends. It took us most of the afternoon, and a bit of time after dinner. A lot of time was spent figuring out the right ratio for the skin though, so if we had gotten that right the first time round we'd have been a lot faster. In any case , our mooncakes were very well received, so the effort was worth it. This recipe is definitely a keeper!

Red Bean Paste (Tao Sar)

red beans , water , pandan leaf , cooking oil (flavourless) , golden syrup , salt
red beans
['red beans']
pandan leaf
['pandan leaf']
cooking oil (flavourless)
['cooking oil']
golden syrup
['golden syrup']

Optionally soak red beans overnight to soften.

Place red beans in a pot and add enough water to cover the beans, plus a bit. (If you're using a pressure cooker, err on the side of adding more water.) Add a few pandan leaves, tied into a knot. Cook the beans in the pot till they become very soft, and you can easily crush them between your fingers. Remove from heat.

Mash the beans into a fine puree. You can do this using a food processor or a food mill. If the mash is not smooth enough, go through it with a sieve to remove any larger chunks.

In a wok, add a fair amount of oil and heat. Add the bean puree. If you have a large amount of puree, split it into batches or it'll be hard to work with. Fry the puree. Add a tiny pinch of salt and generous amounts of golden syrup. The puree, oil and syrup will mix together to form a paste.

Add more oil if it seems too dry, and more golden syrup if its not sweet enough. Keep frying till the paste turns shiny and a very dark brown, almost black. It should look like the tao sar you find in steamed tao sar buns.

Once the tao sar is done, remove from heat and leave it to cool.

Chocolate Ganache

equal parts of dark chocolate and heavy cream
equal parts of dark chocolate and heavy cream
['dark chocolate', 'heavy cream']

Chop up the dark chocolate.

Bring the heavy cream to a simmer. Add the heavy cream to the chocolate. Let stand for 1 minute. Whisk to form a smooth mixture. Leave it at room temperature over night to reach a frosting consistency.

Addendum: After whisking, add a shot of kahlua.

Snowskin for Mooncakes

  • 100 g koh fun, also known as fried glutinous rice flour
  • 100 g glutinous rice flour
  • 150 g icing sugar
  • 70 g butter or some other shortening, cut into small cubes
  • 210 ml water, ice-cold
100 g koh fun, also known as fried glutinous rice flour
['koh fun']
100 g glutinous rice flour
['glutinous rice flour']
150 g icing sugar
['icing sugar']
70 g butter or some other shortening, cut into small cubes
['butter', 'shortening']
210 ml water, ice-cold

This recipe is based on a similar recipe from, by Amy Beh.

Sift koh fun, glutinous rice flour and icing sugar into a bowl. Add the butter and work it into the flour mixture till it becomes crumbly (like when making short crust pastry).

Slowly introduce the water and mix to form a dough. If the dough is too sticky, add more koh fun. If it doesn't stick well and breaks apart too easily, add more glutinous rice flour.

Use dough immediately.

Red Bean and Chocolate Snowskin Mooncakes

  • koh fun, also known as fried glutinous rice flour, for dusting mooncake mould
koh fun, also known as fried glutinous rice flour, for dusting mooncake mould
['koh fun']
Red Bean Snowskin Mooncakes:
  • tao sar
  • peanuts, chopped and roasted
  • snowskin for mooncakes
tao sar
['red bean paste (tao sar)']
peanuts, chopped and roasted
snowskin for mooncakes
['snowskin for mooncakes']
Chocolate Snowskin Mooncakes:
  • chocolate ganache, with a shot of kahlua added
  • hazelnuts, whole and roasted
  • snowskin for mooncakes
chocolate ganache, with a shot of kahlua added
['chocolate ganache']
hazelnuts, whole and roasted
snowskin for mooncakes
['snowskin for mooncakes']

Take a portion of the filling you wish to use. The size of a portion depends on your mooncake mould; make a few test mooncakes to figure out how much you need.

If making tao sar mooncakes, add some of the chopped peanuts into the portion of filling. If making chocolate mooncakes, place a hazelnut in the centre of the portion of filling.

Shape filling into a ball.

Take a portion of the snowskin and shape into a ball. Place a piece of cling wrap on the work surface, and place the snowskin ball onto one side of the cling wrap. Fold the cling wrap into two so that the snowskin is sandwiched in between the cling wrap. Use the palm of your hand or some other flat object to flatten the snowskin to form a circular disc. Keeping the cling wrap on, use a rolling pin to further flatten the snowskin till it is of the desired thinness. Thinner is better, but more tricky to work with. Make sure the snowskin does not tear or break apart.

Uncover the half of the cling wrap that is on top of the snowskin disc. Place a ball of filling in the centre of the disc. Use the cling wrap to bring the snowskin up around the filling, and wrap the filling with the snowskin. The cling wrap is meant to prevent the snowskin from sticking to your fingers and tearing.

Tightly seal the snowskin around the filling. Carefully remove any excess snowskin. You should now have a ball with an inner layer of filling and a thin outer layer of snowskin.

Lightly dust the mooncake mould with koh fun. Place the ball into a mooncake mould, and press it in firmly to shape. Remove the finished mooncake from the mould; if it doesn't come out easily, give the mould a few sharp knocks on the sides.

Repeat for however many mooncakes you wish to make.

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