Nothing sounds better than a warm bowl of homemade Zenzai (Oshiruko) or sweet red bean soup with toasted mochi rice cakes! I’ll show you 3 ways to make this popular winter dessert in Japan with either homemade or store-bought ingredients.
To Make the Zenzai with Dried Azuki Beans (4–6 bowls)
Gather all the ingredients.
Option 1: Pressure Cooker Method
Rinse 1 cup azuki beans carefully until the water is clear. Discard any damaged beans that are floating. Drain the water and transfer the beans to the pressure cooker (I use an Instant Pot).
Add 4 cups water. Cover and lock the lid of your pressure cooker. Make sure the steam release handle points at Sealing and not Venting.
Turn on your pressure cooker and select High pressure for 15 minutes (or 10 minutes for slightly firmer beans). For an Instant Pot, select Manual or Pressure Cooker mode, select High pressure, and adjust the cooking time.
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.
When it’s done cooking, the Instant Pot will switch automatically to the Keep Warm mode. Let the pressure release naturally for 30 minutes. Before you open the lid, turn the steam release handle to Venting and release any leftover pressure. For a stovetop pressure cooker, remove the pot from the heat and let the pressure release naturally.
Add 1 pinch Diamond Crystal kosher salt (to taste) and ¾–1 cup sugar into the pot.
Press the Sauté button and select Low heat. Stir occasionally for about 5 minutes until the sugar dissolves completely.
After cooking for 5 minutes, the soup will be a bit darker in color, too. Keep it warm while you prepare the mochi (please scroll down).
Option 2: Stovetop Method
Rinse 1 cup azuki beans carefully until the water is clear. Discard any damaged beans that are floating, then drain the water.
Put the azuki beans and 4 cups water in a pot.
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 1½ hours. Tip: The otoshibuta will prevent the beans from dancing around too much. You can make your own with aluminum foil.
Some water will evaporate, so add more water as needed to keep the beans submerged. After 1 hour, pick up one bean and mash it with your fingers. If it mashes easily, it‘s done. Otherwise, cook for another 15 minutes and check. Add ¾–1 cup sugar and 1 pinch Diamond Crystal kosher salt (to taste) and cook over low heat, stirring occasionally, until the sugar dissolves completely. Keep it warm while you prepare the mochi (please scroll down).
To Make the Zenzai with Red Bean Paste (1 bowl)
In a small saucepan, combine store-bought ½ cup sweet red bean paste (anko) or homemade red bean paste and ½ cup water. Bring it to a boil. Add 1 pinch Diamond Crystal kosher salt (to taste) and mix well. Adjust the consistency by adding water or reducing the soup. Keep warm while you prepare the mochi (see the next step).
To Prepare the Mochi
Cut 4 pieces Japanese rice cake (mochi) into halves or quarters. Place them in the toaster oven (or the oven). If you‘re using fresh homemade mochi, add it to the soup to warm it up. If it‘s frozen, then boil it in a pot until soft.
Toast the mochi until puffed up and nicely brown, about 10–12 minutes.
To Serve
Serve the red bean soup and mochi in a bowl. Enjoy!
To Store
Transfer the soup to an airtight container and store in the refrigerator for up to 4 days and in the freezer for up to a month. Prepare the mochi right before you serve the Zenzai (Oshiruko).