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Nothing sounds better than a warm bowl of homemade Zenzai or Oshiruko (red bean soup) with toasted mochi! I’ll show you 3 ways to make this popular winter dessert in Japan.
Zenzai (ぜんざい) is a traditional Japanese dessert soup made with azuki beans. This sweet red bean soup is served hot with mochi (rice cake) or shiratama dango (glutinous rice flour dumplings) inside the soup.
Slightly sweet, with a gentle fragrance from the red beans, the dessert soup has the instant magic of warming up one’s soul. The toasty, chewy mochi makes everything even better! It is one of those dishes that brings many cozy memories of my childhood. I couldn’t resist Zenzai whenever it’s offered. Although it’s a wintertime dessert, I crave and enjoy making it all year round (especially in the cooler climate I live in!).
With a pressure cooker or ready-to-use red bean paste, we can make this red bean soup in no time!
What is Zenzai (Oshiruko)?
Zenzai (ぜんざい, 善哉) is basically a soup made from boiling azuki beans with sugar and salt. You might have heard of a different name for this dessert. Oshiruko(お汁粉) or Shiruko is used in the east of Japan where boiled azuki beans are crushed into a smoother paste and become more watery soup than Zenzai.
Quick Review – Zenzai vs. Oshiruko
East of Japan (East of Nagoya, including Tokyo)
- Chunky red bean soup OR soup-less chunky red bean over mochi is called Zenzai.
- Soupy red bean soup without any beans is called Oshiruko.
West of Japan (West of Nagoya, including Osaka)
- Both chunky and fine red bean soups are called Zenzai.
3 Super Easy Ways to Make Zenzai (Oshiruko)
Method 1: Use a Pressure Cooker
If you have a pressure cooker, you can make Zenzai (Oshiruko) much faster. I have an Instant Pot, so here I share how to make the delicious red bean soup using uncooked azuki beans in exactly one hour!
I love my Instant Pots (I have two models this and this) and make this recipe all year round using them. Compared to the stovetop method, pressure cooking really cuts down my time in the kitchen and it’s been a lifesaver! I can do other chores while preparing my favorite, delicious red bean soup!
Method 2: Cook in a Pot over Stovetop
You don’t have a pressure cooker? No worries, I’ll show you how to make it in a traditional method!
Method 3: Use Red Bean Paste
If you want to make Zenzai as quickly as possible, there is even a faster way. Use store-bought red bean paste. You just need to remember they tend to be a bit sweeter than your homemade version, so you might need to adjust the sweetness.
Or if you end up making a big batch of homemade red bean paste (Anko), you can enjoy Zenzai any time! I keep mine frozen all the time and make various Japanese sweets such as Dorayaki, Daifuku, or Dango.
A Great Use of Mochi from Kagami Biraki
Every year January 11th is Kagami Biraki (鏡開き) in Japan. It is a traditional Japanese ceremony to break the ornamental mochi and eat it for good health and fortune for the New Year. You can read more about this cultural ceremony and tradition in my other post.
There is one thing you have to remember for the Kagami Biraki ceremony: never “cut” the mochi when you break it into pieces. The action reminds the Japanese people of Seppuku (切腹), ritual disembowelment during the old times, and they believed it as a sign of bad luck. Therefore, the common way is to break the mochi with a wooden hammer or do it with your hands.
After mochi is broken into pieces, we toast them until nicely brown and put them in Zenzai to enjoy!
Japanese Ingredient Substitution: If you want to look for substitutes for Japanese condiments and ingredients, click here.
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Nothing sounds better than a warm bowl of homemade Zenzai or Oshiruko (red bean soup) with toasted mochi! I’ll show you 3 ways to make this popular winter dessert in Japan.
- 1 cup azuki beans (7 oz)
- 4 cups water
- pinch kosher/sea salt (I use Diamond Crystal; Use half for table salt)
- ¾ cup sugar (6 oz; typically for 200 g azuki beans, 150-200 g sugar is used)
- 3.5 oz red bean paste (anko) (roughly ½ cup; for homemade anko recipe, click here)
- ½ cup water (add more if you desire)
- pinch kosher/sea salt (I use Diamond Crystal; Use half for table salt)
- 4 pieces kirimochi or homemade mochi (you can buy kirimochi or make my homemade mochi recipe or shiratama dango recipe)
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Gather all the ingredients.
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Rinse the azuki beans carefully until water is clear. Discard any damaged beans that are floating. Drain water and transfer the beans to the pressure cooker (I use an Instant Pot).
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Add in 4 cups of water. Cover and lock the lid of your pressure cooker. Make sure the steam release handle points at “sealing” and not venting.
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Turn on your pressure cooker and select High Pressure for 15 minutes (10 minutes if you prefer to keep the beans slightly firm). If you’re using an Instant Pot, press “Manual” or “Pressure Cooker”, select “high pressure” and adjust the cooking time.
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If you are using a stovetop pressure cooker, cook on high heat until high pressure is reached. Then reduce the heat to low to maintain the pressure for 15 minutes.
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When it’s done cooking, the Instant Pot will switch automatically to the “Keep Warm” mode. Let the pressure slowly release by itself for 30 minutes (Natural Release). Before opening the lid, turn the steam release handle to “Venting” and release any leftover pressure. If you’re using the stovetop pressure cooker, remove the pot from the heat and let the pressure release naturally.
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Add salt and sugar into the pot.
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Press the “Saute” button and select “Low” heat. Let the sugar dissolved completely, stirring occasionally, about 5 minutes.
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After cooking for 5 minutes, the soup will be a bit darker in color, too. Keep warm and start preparing the mochi (please scroll down).
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Rinse the azuki beans carefully until water is clear. Discard any damaged beans that are floating and drain.
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Put the azuki beans and water in a pot.
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Bring the water to a boil over medium-high heat. Once boiling, put an otoshibuta (drop lid) over the azuki beans. Turn down the heat to medium-low and keep it simmering for the next 1 to 1.5 hours. Tip: Otoshibuta will prevent the beans from dancing around too much. You can make it with aluminum foil.
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Water will evaporate so you need to keep adding water so the beans are submerged. After 1 hour, pick one bean and mash it with your fingers. If it is mashed easily, it's done. Otherwise, cook another 15 minutes and check. Add sugar and salt and let the sugar dissolved completely, stirring occasionally. Keep warm and start preparing the mochi (please scroll down).
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In a small saucepan, combine the store-bought red bean paste or homemade red bean paste and water and bring it to a boil. Add a pinch of salt and mix well. Adjust the consistency by adding or evaporating water. Keep warm and start preparing the mochi (see next step).
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Cut the kirimochi into halves or quarters and place them in the toaster oven (or the oven). If you're using the fresh homemade mochi, add it in the soup to warm up. If it's frozen, then boil it in a pot till soft.
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Toast the mochi until puffed up and nicely brown, about 10-12 minutes.
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Serve the red bean soup and mochi in a bowl and enjoy!
Other Delicious Sweets on Just One Cookbook:
Editor’s Note: This post was originally published on Mar 12, 2012. It’s been updated with new images and additional pressure cooking method in the recipe in January 2020.
Tried this tonight with Shirakiku brand koshi an–now in a easy to squeeze out package– and homemade mochi. My family enjoyed the quick treat on a rainy night in Honolulu. I look forward to trying your other recipes!
Lori Bruner Okamura
Hi Lori! I have been thinking about making this for several days now. I’m a huge anko fan and I can eat it everyday… 🙂 So happy you enjoyed this. Thank you for letting me know!
Nami, the recipe for Red Bean Soup looks like something I would want to try. I would also like to know where you purchased your “props” the tiny getta sandals? My daughter would love to have those on her table the next time she prepares a Children’s Day feast.
Thank you,
Sharon
Hi Sharon! I hope you enjoy this recipe! I think I got this geta from Daiso (Japanese $1 store). They have small (and cheap) Japanese decorations stuff there. They have online store, but they only sell selected things… Sorry I cannot help much. 🙁
Here’s the link for Daiso: http://www.daisojapan.com/
I love zenyai, thank you for this recipe and for your wonderful site!
I have already made your mochi, and it was perfect.
Domo!
Hi Tanya! So happy to know you like zenzai too! This is a wonderful snack in winter months. I enjoy eating mochi too, so I always look forward to zenzai with mochi on cold days. 🙂 Glad to hear you enjoy my mochi (strawberry mochi?) recipe. Arigato!
Hi Nami,
I tried making your zenzai soup ytd, overall it was quite good, and I already want to try the recipe a second time. Just a quick question, I used anko that I had chilled in the freezer and boiled it with water, however the two don’t seem to be able to blend? The red beans and water remained separate even after I had boiled them together, is it supposed to be like that?
I toasted the mochi in my oven and they turned out perfect! helped myself to two big chucks!
Hi Marilyn! It depends on how you cooked anko (if homemade). If you can still see the bean, then the outcome of zenzai is liquid + beans. Only if you use “koshi an” (paste texture of red bean), the liquid will be thicker and blend in. If you feel it’s watery, cook a little longer to reduce a bit. If you prefer the liquid to be thicker, then you may want to use koshi an (I don’t have a recipe yet, but Japanese grocery store sells koshi an (you wont’ see any bean shape). Hope this helps…. 🙂
Thanks Nami!
I’m using canned sweetened red bean paste.
I’ll try to reduce it more next time.
お返事ありがとうございます!
どういたしまして!:)
Can you show us how tomake mochi from scratch?not the trational one though,i hear its labor intensive. But i heard that there are other ways to make it…i miight not find mochi rice though…some sort of flour? The stovetop version please,im uncomfortable using the microwave…
Hi Mikah! Yeah the traditional mochi is a bit labor intensive. You can make shiratama dango which takes about half hour or less to make.
I have one tutorial here that requires cooking over stove.
https://www.justonecookbook.com/recipes/mitarashi-dango/
You can use mochiko (some people think it’s easier to find this one), but you need to adjust the amount of water (use less water).
Hope this helps, and enjoy! 🙂
Just want to tell u that ur photographs keeps getting better n better. Love that touch of mini getta next to the zenzai
Hi Susan! Aww you’re so kind. Thank you very much! I’m glad you noticed the geta. I used to put more small props in the picture… 😀
When you bake the dumpling are they already boiled or is it the raw dough? And do you have suggestions for the baking temperature and time?
Hi Graig! I updated the recipe with step-by-step picture from another post. You would toast in a toaster oven or oven (or even frying pan).
I have a video of toasting mochi in the toaster oven here (@0:50).
https://www.justonecookbook.com/how-to-enjoy-japanese-mochi/
Hope this helps!
Hi Nami,
My family loves your red bean soup so I make it on a weekly basis. Just wondering if you have a recipe for sweet black sesame soup. Thanks.
Hi Darlene! I’m so happy to hear that. I haven’t had it for a while and I definitely want it with mochi!
I had never heard of the sweet black sesame soup, so I googled. I learned that it’s a Chinese dessert. I haven’t tasted this before. I have to give it a try when I see it.
My blogger friend has the recipe: http://www.chinasichuanfood.com/black-sesame-pastesoup/
Hope that helps!
Can I make this recipe with koshian?
Hi Haru! Yes, you can make it with Koshian. 🙂
Sweet!
Thank you. I’m gonna try and make this on the weekend. Looks good.
Aaah finally I found this recipe! First time I try this was when I hiked Mount Tsukuba last year, and now I’ve been craving it again because of the sweetness from anko and chewiness from the mochi, love it! Thank you for sharing it Nami-san!:)
Hi Fisti! I’m excited that you can re-create this recipe at home! Hope you enjoy! I LOOOOOOOVE zenzai. It’s my favorite sweet treat all year around. 🙂
My mother is from Nemuro, at the easternmost point in Hokkaido, and even though our family lived in Tokyo when I was born, I never had ozoni for New Year’s growing up. We always had oshiruko. Thanks for posting this recipe and information, Nami! It’s rare these days in Denver, Colorado to find oshiruko in home or definitely any restaurants, so it’s nice to relive my childhood through your culinary expertise!
Hi Gil! I’m not sure if you can read Japanese, but this is an interesting map of Japan showing which location eat what type of Ozoni.
https://j-town.net/tokyo/research/results/198552.html?p=all
Blue: Clear soup (Kanto style Ozoni)
Red: Miso (Kansai-style Ozoni)
Orange: Zenzai / Oshiruko
Green: Others
My family lives in Kanto, but my grandma (my mom’s side family) is from Kyoto area so we eat white miso ozoni. 🙂
I hope you enjoy making Oshiruko at home. With azuki beans (pretty easy to access even at health store), you can make this at home! 🙂
We followed the recipe exactly, and it came out delicious. However, next time, we’ll probably use even less sugar and let the instant pot cook the beans for a bit longer, since this time the beans were slightly undercooked for our personal taste.
Hi Angie!
Please feel free to adjust sweetness and cooking time for your liking!😉
Thank you very much for trying this recipe and for your kind feedback!
I have some freshly made omochi from my grandma and want to make this red bean soup. Can you tell me if the leftover soup can be frozen, or how long it will be good for in the fridge? I will make it in my instapot so can I reheat it on the stove top? Thank you!!
Hi Annette!
You are so lucky to have freshly made Omochi! It’s the best! 😋
You can transfer the red bean soup in an airtight container and store it in the refrigerator for up to 2-3 days or in the freezer for up to 1 month.
And yes. You can reheat it on the stovetop with low to medium heat.
Enjoy!
Hello! I’m half Japanese and love Zenzai-but now with trying to be a little healthier- can I substitute the sugar for erythritol or other sweeteners? Will it take away from the traditional taste I love?
Hi Rina,
Thank you very much for trying this recipe!
We have never tried this recipe with erythritol and don’t know how the outcome will be. Sorry…
Let us know how it goes!
I don’t have any Anko (couldn’t find any). All I have is a can of crushed adzuki from Mitsuwa. Will this work? I just got some fresh mochi from Mitsuwa, but cannot stand how bland it is on its own, so I wanted to make this with it and my canned Adzuki.
Hi Savannah,
Yes, you can use a can of crushed adzuki by adding water and sugar to your taste.
We hope this helps!
I made azuki an for daifuku mochi. Easy to follow recipe. I appreciated.
Hi Hisashi, Thank you very much for trying many of Nami’s recipe. We are so happy to hear you enjoyed it! Thank you for your kind feedback.