This staple Asian pastry filling is best made from scratch, since store bought is not only hard to find, it’s of highly variable consistency, texture, color and sweetness. Make it yourself and you can control all those factors, and it’s not difficult. Think of it as a sweet Asian version of refried beans, though now that I think about it, adzuki paste’s starchy sweetness reminds me more of thick mashed sweet potatoes. Excellent! Begin by soaking about a three cups of dried adzuki beans (available at Asian markets and/or your nearest Whole Foods in the bulk section) in water for about six hours.
Put the pot on the heat and bring it to the boil. At that point strain the whole mess, pour cold water over them and start again. Bring the beans to the boil a second time, then turn the pot down to a simmer and cook them about one and a half hours, adding water when needed, until the beans can easily be squished to paste between your fingers.
Strain them (your batch will produce more than this…this photo just turned out well)
Now comes the laborious part. That is unless you have one of these strainer attachments for your stand mixer. We used this to make baby food when the girls were younger, but it’s great for making a smooth bean paste, which you have to press through a strainer with the back of a spoon otherwise. That’s not the end of the world, but it’ll take you a good ten minutes of pressing.
Me, I just poured the beans into the insert, attached the little flat blade to the stand mixer, and turned it on. It pushed the beans through the screen in about 3 minutes, leaving a residue of skins (note: this is the remains of a bout six cups of uncooked beans…I made extra in case of mooncake disaster).
The bean starch just got pushed through and ended up in the bowl like so. Nice! You can of course skip this step to make a rustic, chunky bean paste. Me, I like my adzuki bean paste smooth like my (imaginary) Chinese grandmother made it.
So then. Once the paste cools completely it will be quite firm, again, like leftover frijoles refritos. These are cold as I refrigerated them while went out of town over the weekend. To make the finished paste, put four cups of mashed beans in a saucepan add about 3/4 teaspoon of salt…
…and 1 1/4 cups cup of golden syrup or refiner’s syrup to the beans. You can add more or less. The syrup not only keeps the mixture thick, it adds caramel and/or molasses notes to the paste (it also works as a preservative). You can use brown sugar or granulated sugar if you like, though you’ll get a somewhat thinner consistency.
Bring the paste up to the boil. Now then, since this paste is going into mooncakes and I wanted a nice purply sunset color for my cooked egg moons — rather than gray/red — I added some red food coloring. Do as you will!
Then I turned the paste out onto a sheet pan for faster cooling.
After about half an hour it was ready to be used or refrigerated again until the time was ripe!