The following makes 14-16 mooncakes.
*Note: Please scroll to the part after the jump for instructions on making the "Snow Skin" (冰皮) variety, which I have updated in 2016.
For the custard filling (to be done the night before):
60 grams of white sugar
20 grams of cake flour
25 grams of custard powder
25 grams of milk powder
110 mL of coconut milk
40 grams of unsalted butter
8 salted duck egg yolks (check local Asian supermarket)
1 egg yolk
Pinch of salt
1. Combine the sugar, cake flour, custard powder, milk powder and salt together. Add in 1 egg yolk and coconut milk and stir to combine well. Press down on all lumps.
Weigh out the dry ingredients and mix them well.
Mix in the wet ingredients. Be sure it is smooth.
2. Put the salted egg yolks through a food processor (or chop very finely) and place the butter on top of the yolk in a bowl.
The chopped salted egg yolks should have a texture like cornmeal.
3. On high heat, steam the (1) and (2) separately, each for 7-8 minutes. Steam (2) first.
4. Once the salted egg yolks have gone through the steaming, mash it until it is very smooth.
Press down hard with the back of the spoon.
5. After mixture (1) has been steamed, combine the salted egg yolk mash with it. Blend well using a hand blender until smooth. If there are lumps, mash them with the back of a spoon.
Work quickly while hot so the liquid would not congeal.
6. Finally, pass this mixture through a fine sieve to remove any lumps in the salted egg yolk. This needs to go in the fridge to firm up first to make it easier to scoop. Around 3 hours.
Press the bits through the sieve to make the texture smooth.
Voila! The resulting velvety custard.
7. Remove from the fridge. The custard should now have a firmness like that of clay. Using a melon baller (2 teaspoon size), portion the custard filling into small circular lumps onto a tray lined with Silpat or grease paper.
8. This then goes into the freezer overnight to really firm up.
For the wrapping:
230 grams of cake flour
120 grams of unsalted butter
75 grams of sugar
Half an egg
25 mL of coconut milk
20 grams of custard powder
9. This is essentially a twist on the shortbread recipe. Let the butter come to room temperature first. You can even put it in the microwave to expedite the process. Add in the sugar and combine well.
It is easier to work through the butter if it is at room temperature - solid yet smooth. Don't put it in microwave for too long that it completely melts into liquid either.
10. Add in custard powder, cake flour, coconut milk and half of an egg. Combine well and knead the dough for a while to remove air pockets.
Knead well so the powders are thoroughly incorporated throughout the dough.
11. Place in the fridge to firm up, at least a few hours. The target texture should be very firm, if not hard.
Wrap in cling film to keep it moist inside the fridge.
To make the mooncakes:
12. This is probably the trickiest step. Action must be quick or else the mooncake will lose its shape upon stamping. Set a tray with a Silpat in the fridge. Dust hands, rolling pin, work surface and mold with flour.
Here, I use a small metal tube as a rolling pin. Also, when dusting the mooncake mold, be sure to coat the sides with flour too.
13. Portion out the skin (around 25 grams each) and roll it to a thickness or two pennies. Place the sphere-shaped of filling in the center, pull the edges up and pinch the ends together to meld, like folding a dumpling.
Getting the custard into a spherical shape when it has hardened in the freezer is a nightmare, especially since hands have plenty of body heat. That is why we first portion out the custard and shape them into balls before they even hit the freezer.
14. Using subtle force, roll the dumpling back and forth between the palms of the hands to form a ball. It is imperative to work quickly or else the body temperature will melt the center. The ball should be big enough to fit snugly into the mold. This way, when the mold is pressed, the mooncake will get well-defined groves around the perimeter.
15. Once the ball shape is formed, place the mold over the spherical dumpling. Press down firmly until there is adequate resistance. Trim off any excess skin should there be any.
There it is with clear-cut patterns.
16. Gently lift the mold up and place the molded mooncake onto the tray in the fridge immediately. Repeat until all ingredients are consumed.
17. Let the mooncakes sit in the fridge for 2 hours to firm up before baking. Meanwhile, preheat the oven to 395 Fahrenheit (200 Celcius).
Having the mooncakes up on a cookie sheet in the fridge before baking. The spherical one to the far right is used to test baking temperature and times.
18. When time is up, brush a super thin layer of egg wash onto each mooncake. Bake the mooncakes in batches of 5 for 5 minutes per cycle.
19. After each batch of baking, remove the mooncakes and place on a lined cookie sheet to cool. Do NOT place on a cooling rack as the metal may cut through the molten center. Let the mooncake cool to room temperature.
Some of these do not hold up too well. You win some, you lose some.
20. Once that is done, the mooncakes are ready and can be eaten now. To pack up the rest, place the mooncakes back in the fridge for an hour to let the center congeal. To serve, microwave each mooncake on high for 10 seconds (not a second more, important). These little pastries are much more delicious slightly warm than cold.
2016 Update
This year, I have made a variation to the custard mooncakes by placing them in a 'snow skin' wrapper. Rather than eating them hot, these are eaten cold. I personally find them a lot easier to make because of more straightforward temperature control; and they are just as delicious. Let's get to it.
And for a variation - you can use the same custard filling but for "snow skin" (冰皮) too. They taste just as delicious cold as they are warm.
Snow Skin Wrapping:
45 grams of glutinous rice powder
35 grams of rice powder
20 grams of wheat starch
20 grams of vegetable oil (can use sunflower seed, grape seed or canola oil)
185 mL of whole milk (higher milk fat content makes for a glossier skin)
50 grams of granulated white sugar
1. Combine all dry ingredients together and mix well.
2. Add in the milk and oil. And stir to remove any lumps.
3. Strain the mixture through a fine sieve to remove any remaining powder lumps. Let sit for 30 minutes.
4. It is imperative to cover the bowl up with glad wrap or tin foil to prevent excess moisture going in. Otherwise, it would make the dough too sticky to fold. Once covered, steam for 30 minutes on high heat. Remove and let cool. While still hot, fold the dough so it is well incorporated.
To form:
1. First is to toast some glutinous rice powder. Place them over a pan on high heat until slightly browned and smoke starts coming out. Let cool.
2. Dust the surface as well as the mould with the toasted powder to prevent it from sticking. Dust the mould after every press.
3. Measure out 35 grams of the dough and work the dough to remove excess oil. Flatten it to the thickness of a coin. Dust liberally with the toasted powder should it become sticky at any point.
4. Place the frozen custard filling in the center and wrap it up. Roll the final product into a sphere and place in mould. Press twice and voila! There is the mooncake.
A full demonstration of the folding process can be seen in the video below:
Please feel free to reach out and leave a comment should there be any questions. In the meantime, have a fabulous mid-autumn festival!