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!

Other Delicious Sweets on Just One Cookbook:

Taro Tapioca Pearl DessertMitarashi Dango

Wish to learn more about Japanese cooking? Sign up for our free newsletter to receive cooking tips & recipe updates! And stay in touch with me on Facebook, Pinterest, YouTube, and Instagram. 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.