In recent weeks, I’ve been experimenting with more and more Asian-inspired flavors and ingredients. It all began when my friend Yukiko introduced me to a Japanese dish that has become one of my top favorite recipes of all time. My discovery then furthered when I got my hands on Elizabeth Andoh’s outstanding recipe book Kansha. In it, she focuses on shojin ryori, or “temple cooking”, which in line with the Buddhist principle of non-harm is plant-based. I now realize how much more there is to Japanese cuisine than the usual sushi, maki rolls and mochi that we’re all familiar with. I’ve tried about seven or eight recipes from this book so far, including cold buckwheat noodles with a tangy umeboshi sauce and herbaceous shiso, creamy/crispy kabocha squash croquettes, candied sweet potatoes and pancakes filled with red-bean jam (check my Instagram from a few weeks ago for photos of all these).
In Japanese cuisine, an effort is made to combine a range of colors, textures and flavors in each dish. Pasta with a creamy sauce is paired with a crunchy, tangy salad made of colorful carrot, cucumber or red pepper. White rice is cooked together with a few spoonfuls of black rice to become lavender, and is then studded with bright green edamame beans. Sweet preparations may include a few drops of soy sauce or a touch of miso to temper the sugary taste. Such combinations result in works of art that are pleasing to both the palate and the eyes.
It was in this context, then, that I began imagining ways of integrating these principles and ingredients into familiar Western dishes. After my discovery of red-bean (azuki) jam, I wondered how it would taste paired with chocolate. This fusion recipe is the result: a traditional chocolate layer cake with a sweet azuki filling, topped with a sprinkling of powdered sugar and kinako (toasted soybean flour).
I’m quite pleased with the way this experiment turned out. The dark, rich chocolate goes very well with the sweet paste, which gains a caramel-like dimension from the soy sauce. The kinako adds an interesting color contrast as well as a nutty, toasted flavor. And with the traditional layer cake form, it would be the perfect birthday cake for anyone who (like me!) enjoys Asian cuisines and is not a huge fan of cakes slathered in frosting. 😉
This recipe is also a good example of mindful, contemplative shojin cooking (“slow food” in contrast with today’s trends), since the azuki paste takes time and watchfulness to make. I recommend making it the day before the actual cake.
So, what exactly are azuki beans? They’re smallish red legumes with a white stripe and must not be confused with kidney beans (see below). I get mine from my local organic shop, but they should also be available online.
You may already have heard of azuki (sometimes spelled adzuki) beans, or red beans, being used in Asian desserts. When I lived in San Francisco, I would sometimes buy something called a mooncake, which has a red-bean filling, when I passed through Chinatown. If you live near an Asian supermarket, you may be able to get pre-made red-bean paste there. But if you’re a do-it-yourself type, like I am, or want your filling to be free from preservatives and coloring agents, or just less sweet than the ones found at stores, you can make your own with the recipe below. In making this jam, I drew inspiration from two recipes: Andoh’s and this one from the blog Just Hungry (but any errors in the following are purely my own fault).
This azuki preparation (tsubu-an in Japanese) can also be spread on toast or pancakes like jam, used as a topping for oatmeal or rice pudding, or even served with cheese in lieu of a fruit chutney. The blogger behind Just Hungry recommends enjoying it with ice cream and strawberries, which does sound pretty good.
Makes about 2¼ cups of filling. Can be made a day or two before the cake.
- 1 cup (200 g) dry azuki beans
- ¾ cup to 1 cup (150 to 200 g) granulated sugar
- 1 teaspoon (5 ml) soy sauce, or more to taste
Equipment needed: food processor or high-power blender (alternatively, a potato masher or fork and some patience).
Place the dry beans in a bowl and add enough water to cover them. Allow to soak for 24 hours (keep in the fridge for best results). The beans will lose their red color as they soak. If you don’t have time for this soaking step, you can skip it, but the cooking process will take longer.
At the end of the soaking stage, rinse the beans and transfer them to a large stock pot. Fill it with enough water to cover the beans (never add salt when cooking legumes, except at the very end) and bring to a boil. Allow to boil for one minute, then drain and rinse the beans with cold water.
Return the beans to the pot, refill with fresh water and bring to a boil a second time. Allow to boil for one minute as before, then drain and rinse the beans again. Rinse and wipe the inside of the pot with a sponge to remove all residue. Although lengthy, this process ensures that all impurities are removed. If you have plants, you can save the cooking water to water them with once it’s cool.
Now you’re ready to cook the beans for real! Return them to the pot and refill with fresh water to about 1 inch (2 cm) above the beans.
Bring to a boil, then reduce the heat to low and simmer, covered, until the beans are soft enough to crush between your thumb and pinky finger (45-60 minutes). If you did not soak the beans before cooking, this step may take longer. Check them every once in a while during this time, adding more water if the level goes down too low and they aren’t done yet. If you have a table in your kitchen, this is a good time to take a seat and delve into a good book.
When the beans pass the thumb-and-pinky test, drain them but reserve about a cup of the cooking water.
Return the beans to the pan and add about ½ cup of the reserved cooking water back in, or more as needed—the idea is to have just enough to keep the beans from getting too dry and sticking.
Add the sugar and continue to simmer, stirring occasionally with a wooden spoon, until you have a thick syrupy sauce (about 15 minutes). The beans will darken in color once the sugar is added. If at any point they become too dry, add more of the reserved cooking water in small amounts (¼ cup at a time).
Now add the soy sauce, stir to incorporate, and taste. If it seems too salty to you, add a bit more sugar. If it seems too sweet, add a bit more soy sauce, or ¼ teaspoon salt if you need more saltiness but want to limit the soy sauce flavor. Simmer for a minute or two more, then remove from heat and allow to cool.
Transfer the beans to a food processor or high-power blender and pulse or purée until you have a smooth, paste-like consistency.
Mine ended up looking like this because the little food processor I use is not super powerful. You could also opt to mash it with a potato masher or similar. It’s fine if a few chunky bits remain.
Store the azuki filling in the refrigerator and use within 5 to 7 days.
Makes two cake layers.
- 3 cups (375 g) all-purpose flour
- 1¼ cup (250 g) white or raw cane granulated sugar
- 1 teaspoon (7 g) salt
- 2 teaspoons (9 g) baking soda
- ½ cup (40 g) unsweetened cocoa powder, sifted
- 3 teaspoons (15 ml) vanilla extract
- ¾ cup (177 ml) neutral-flavored oil, like sunflower or canola
- 2 tablespoons (30 ml) white vinegar
- 2 cups (500 ml) cold water
- a few tablespoons powdered sugar
- a few tablespoons kinako (roasted soy flour), optional
Equipment needed: two 8-inch (20-cm) round cake pans (or bake them in two stages using one pan—be careful to divide the batter evenly). You can use pans with a larger diameter if you like, but the layers will be lower and the cake shorter than what you see in these photos.
First, preheat your oven to 350°F (180°C). Combine all the dry ingredients in a large mixing bowl. I used a raw cane sugar in this case, but regular white granulated sugar is fine.
Combine the liquid ingredients in a smaller bowl and whisk to combine.
Prepare your cake pans by lining them with some baking paper. Apply a bit of oil to the pan first to make the paper stick. I like to leave little “handles” like these on the sides to be able to dislodge the baked cakes more easily.
Whisk the dry ingredients together and then add the liquid ingredients to the bowl with the dry mixture. Whisk everything together just until combined, being careful not to over mix as this would make the cake stiff.
Transfer the batter to your prepared baking pans, diving it evenly between the two, and place in the oven. Bake at 350°F (180°C) for about 20 minutes.
Check for doneness at this point by inserting a toothpick or fork into the center of the cakes. If it comes out clean, the cakes are done. If not, put them back in the oven for another five minutes and check again. When fully baked, place them on a baking rack or stovetop to cool. Allow the cakes to cool completely before attempting to remove them from the pans.
You will notice that each cake layer has a domed shape. The tops will need to be leveled before you can assemble the two layers.
Using a large knife, carefully slice off the top of each cake, depositing the pieces you cut off into a bowl. Crouch down to look at the cake from the side, at tabletop height, to check whether it’s even enough.
It will look something like this. Remove the baking paper from underneath it and transfer it, cut side facing up, to a clean plate.
Apply the azuki filling thickly, spreading it with a spoon or large knife to ensure that it covers the surface evenly. Reserve a small amount to fill in any gaps that remain in the sides once you’ve placed the other cake layer on top.
Now carefully place the other cake layer, cut side facing down, on top of the filling. The cake will have a nicely defined edge along the top. With a frosting knife or flat spatula, fill in any gaps between the two layers with more azuki filling and smooth out the sides. Cover the cake with a cover or an upside-down salad bowl until just before serving. Powdered sugar tents to “melt” into the surface of a cake, so if you apply it ahead of time you will most likely have to do it again and the results will not be as nice. If you will be serving the cake the next day, keep it in the refrigerator until about an hour beforehand.
A few minutes before serving the cake, apply the powdered sugar. I recommend using a sieve such as this one, or a sifter of some kind, to prevent any large clumps of sugar from falling on the surface and ruining the powdered effect.
You can use more sugar than this if you like. It depends how opaque you want the surface to be.
After the powdered sugar, use the same method to sprinkle some kinako on top. Or if you prefer, you can apply the kinako first and then the powdered sugar. It depends which color you would like to be more prominent.
And now you’re done!
After serving, cover the remaining cake and place it in the refrigerator (without preservatives apart from sugar, the homemade azuki paste can go bad if left too long at room temperature).
Variations: Use the azuki paste as cupcake filling: after filling the cupcake cups half-way full with batter, deposit a small dollop of azuki paste in the center and push it down until it’s submerged by the batter. Also try it as a frosting for the top of a single-layer cake, or as a spread for toast, etc. as mentioned in the azuki filling recipe above.
6 thoughts on “Chocolate cake with azuki filling”
You temptress – now I want azuki bean paste! I’m interested that you state “neutral flavoured oil”. I’d have thought a spot of coconut oil might be just the thing for a chocolate cake (you’d have to melt the oil first, but otherwise…)
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Flavorful oils can indeed be very interesting in cakes. Just the other week I had some chocolate cake made with citrus-infused olive oil, and it was amazing! And I’ve made other cakes with regular olive oil with very good results too. For this particular cake, I’d worry that the coconut would compete with the azuki flavor, but I’ve used coconut oil in banana bread, and that was one of the best things I’d ever tasted.
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Coconut and banana bread? Oh god, now I’m ravenous for cake!
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I love what you say of Japanese cuisine, it makes me want to know more. It’s such an “artistic” culture! I tried an azuki/chocolate cake recipe a long time ago, but found it so-so–only, the bean paste was incorporated in the batter. I’m sure your layered cake is a much better option to really enjoy the flavor of the beans… Will have to try it sometime… 🙂
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I was wondering about that too… about what would happen if the beans were mixed right into the batter. It does seem like a delicate flavor that could easily be overwhelmed by chocolate, so it sounds like I made the right move keeping them separate. Kansha is available in French now too, but as a translator I recommend always sticking with the original when possible. 😉
the soy sauce surprised me but I am guessing it’s just doing the same job as salt to bring out the flavour and sweetness? Looks delicious!
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