Oshiruko (Zenzai): Red Bean Soup with Mochi

Oshiruko or Zenzai is a sweet, warming Japanese dessert soup made from boiling red beans and sugar, then topped with mochi. The combination of subtly sweet red bean and chewy mochi makes this warm soup feel homey.

For our sweet red bean soup recipe, we'll show you how to make oshiruko and zenzai. Both are variations of each other made across different regions of Japan. 

While the ingredients are the same, the main difference is in texture. In East Japan, Zenzai is a chunky soup topped with mochi, while Oshiruko is a sweet Anko soup with smooth beans that's more watery. On the other hand, both are done the same way in the West of Japan.

Jump to:

• Ingredients
• Oshiruko (Zenzai) Red Bean Soup with Mochi
• Cooking Tips
• With Shiratama
• With Matcha
• Cold Zenzai
• Calories
• When is it eaten?

Ingredients

To make oshiruko and zenzai, you'll need the following ingredients:

• Red bean paste (Anko)
• Water
• Salt
• Shelf stable mochi

As we've mentioned earlier, Oshiruko is simple and easy to make. The dish also doesn't require a lot of ingredients but can be customised depending on what toppings you'd like to add. Any other added ingredients will enhance the flavour and give you a better taste. 

Red bean paste (anko)

We'll be using our red bean paste recipe to make anko from scratch. Anko is a sweet red bean paste that makes this dish special. It's made from mashed azuki beans and is used as a filling in lots of Japanese desserts. However, you can buy this in a can form or a packet.

While there are many different textures of Anko paste, like Koshi-an and Oguru-an, the most commonly used for Oshiruko are Tsubu-an and Tsubushi-an.

Tsubu-an is a chunky red bean paste made up of whole beans. Tsubushi-an is a crushed red bean paste. It's our favourite version of this Japanese red bean soup because of its subtle texture when it's dissolved. 

Koshi-an is the creamier and smoother version, as the skin of azuki beans is removed. It is also the most commonly sold version. In terms of taste, you can use Koshi-an for our recipe. However, we recommend making your own crushed red bean paste for the best texture.

Mochi

You'll need shelf-stable mochi or kirimochi. These come in dried form and puff up when toasted. Oshiruko is not the same without the crunchy yet soft-centred mochi.

If you can't find kirimochi, you can make mochi in a microwave. Although fresh ones don't toast well on the stove, you'll still get a lovely chew. 

Salt and water

Salt enhances the sweetness of our soup. You can use any salt you have at home. We just use regular table salt for our recipe. Depending on how thick or thin you like soup, you can adjust the consistency by simmering it for shorter or longer.

Cooking Tips

Storebought red bean paste can sometimes be too sweet, so we like to use our homemade anko paste. However, you can adjust the taste by adding more water.

Don't skip out on adding salt to your oshiruko. The salt helps to enhance the overall flavour, making the taste of the red bean more pronounced.

Make a big batch of red bean paste and keep it refrigerated. It's a little hack so you can enjoy Zenzai any time.

We like to cut the mochi to 2 inches in length or less to make it easier to chew. This goes for any other toppings you like to add.

Besides toasted mochi, you have several topping options to add to our recipe. You can add Shiratama, soft mochi or even matcha. We love adding toasted mochi and shiratama to our red bean paste soup. Otherwise, you can also make it a cold zenzai. If you're feeling extra, add Cherry Blossom Rice Cake to make your red bean soup.

With Shiratama

Here's how to make Shiratama as an oshiruko topping. This will make about 6 shiratama that are 1 inch in diameter. While shiratamako is the best ingredient, you can also use glutinous rice flour to make shiratama. It will turn out very similar but slightly less soft.

Mix ¼ cup of shiratamako, ¼ teaspoon of sugar, and 2 tablespoons of water in a bowl. Knead the dough with your hands until soft and dewy. Roll them into medium-sized balls of 1 inch. Put the shiratamako dough in boiling water and take it out when it floats.

With Matcha

Matcha lovers, this recipe is for you. It tastes similar to the regular oshiruko but with the added earthy and grassy flavour of green tea.

Here's how to make matcha zenzai for 1 serving.

Add 1 teaspoon of matcha in a bowl and pour about ¼ cup of hot water (ideally about 80°C (175°F) over it. Whisk the matcha using a bamboo whisk until all of it has dissolved, and you can see a foam layer at the top of the green tea. If you prefer it sweet, you can also add 1 teaspoon of sugar to the green tea and stir until it's dissolved.

Then, prepare the zenzai or oshiruko according to our recipe. Once it is ready, pour the matcha into the bowl of the oshiruko while it's hot.

Cold Zenzai

Although many locals serve Zenzai during winter or colder seasons, you will find that it also goes well when you eat it as a cold dessert. Amazingly, this can fit in any season or weather. Moreover, you can also chill Zenzai and serve it with a few scoops of ice cream.

There's not much of a difference in taste. It still gives a hint of sweetness, making it a good choice for dessert. 

Calories

A cup of our Oshiruko only has 170 calories. The soup mainly contains healthy ingredients like red beans, water, and rice cakes. However, the calories will increase if you decide to add more sugar or use a sweeter store-bought adzuki paste.

Surprisingly, the calorie count for this dessert isn't as high as you may assume. That means you can enjoy this oh-so-goody dish without worrying about your calorie count.

When is it eaten?

Locals traditionally serve this hot Japanese red bean soup after New Year's Day with Kagami Biraki to warm themselves from the cold. You can also find it during autumn at the rest areas of popular hiking spots in Japan.

It originates from Susuri Dango centuries ago and can now be bought as instant soups in different convenience stores.

The main reason this soup remains a local favourite is not only because of how easy it is to make. Locals often crave this red bean soup the most on colder days, specifically during the December holidays.If you've made our recipe and loved how it turned out, tag us on Instagram @honestfoodtalks.