Sweet Rice Ball Soup Recipe: Silky Mochi Bites in Warm Broth

This sweet rice ball soup recipe brings comfort in every steaming bowl, where delicate mochi bites float in a warm, aromatic broth that tastes like home.

Growing up, I'd watch my Nonna shape these delicate rice balls by hand, their silky texture and subtle sweetness making them a staple during cold Boston winters.

The secret lies in the balance of glutinous rice and the right broth—whether it's classic dashi or a richer miso-infused version—each sip carries that perfect harmony of flavors.

The recipe starts with preparing the rice balls, where glutinous rice is mixed with sweet red bean paste or chestnuts, then carefully shaped into smooth, bite-sized spheres. These are then gently simmered in a lightly sweetened broth until they're tender but still hold their shape.

The broth itself is where the magic happens—simmered with ginger, soy sauce, and a touch of sugar to create that signature comforting sweetness that makes this dish irresistible.

What you'll end up with is a bowl of warmth and tradition, where each spoonful delivers that perfect contrast of soft rice balls against the smooth, flavorful broth.

The aroma alone will transport you to a cozy kitchen somewhere, while the texture—silky mochi bites in every bite—makes it a dish worth savoring. Serve it as a light dessert or a comforting treat after a meal, and you'll understand why this recipe has been cherished for generations.

Perfect for chilly evenings or as a special treat, this sweet rice ball soup is both elegant and approachable. The process might seem delicate at first, but with a little practice, you'll be shaping these rice balls with confidence.

Let's bring a taste of tradition to your table with this timeless recipe.

Ingredients for sweet rice ball soup

Fourteen ingredients bring tradition to your kitchen with these comforting mochi bites.

The glutinous rice is the heart of these mochi bites—Bob's Red Mill or Mochiko brand are my go-tos, but any short-grain works. Sweet red bean paste? Marukyu or Hana Saku from Asian markets have that perfect balance of sweetness. If you're feeling fancy, chestnuts add a luxurious twist—Trader Joe's sells pre-cooked ones in a can, which saves time. For the broth, homemade dashi is ideal, but Kikkoman or Hondashi packets work in a pinch. Just remember: fresh ginger makes all the difference here—look for firm, bumpy roots with no soft spots.

No sweet red bean paste? Substitute with mashed sweet potatoes or apricot jam—both add natural sweetness. Chestnuts too pricey? Swap for diced apples or pears, though they'll change the texture slightly. Miso paste running low? White miso is essential, but you can blend red miso with a bit of water for depth. The soy sauce can be swapped for tamari if you're gluten-free, and if your broth needs more body, add a splash of coconut milk. For shaping, if the rice balls stick, dip your hands in cold water—it makes all the difference.

Store the shaped rice balls in an airtight container with a damp paper towel—keeps them fresh for 3 days. The broth reheats beautifully, so make extra and freeze portions for up to 3 months. I like to portion the soup into individual bowls before freezing—just thaw and warm through. Pro tip: if your rice balls dry out, steam them for 2-3 minutes before serving. Leftovers? They taste even better the next day as flavors meld.

Step-by-step instructions for sweet rice ball soup

Here's how to create silky mochi bites swimming in rich, aromatic broth—comfort food at its finest.

In a medium bowl, combine the 0.75 cup sweet red bean paste (anko), 0.5 cup chopped chestnuts (if using), and 0.25 cup granulated sugar. Add 1 tablespoon cornstarch to help bind the mixture and create a smooth texture. Using a fork, mash everything together until you achieve a thick, spreadable paste with no visible lumps.

This filling is the heart of your rice balls, so take your time here. You want it to be cohesive enough to hold together when rolled but still soft enough to melt slightly in the hot broth. If the mixture feels too dry, add 1 teaspoon water at a time until it reaches the perfect consistency—it should cling together when pressed between your fingers.

Rinse the 1.5 cups glutinous rice (mochiko) thoroughly under cold water until the water runs clear. This removes excess starch that would make the rice gummy. Drain well, then transfer to a saucepan with 1 cup water and 0.5 teaspoon salt. Bring to a boil over medium-high heat, then immediately reduce to low heat and cover with a tight lid.

Simmer for 15-18 minutes until the rice absorbs all the liquid and becomes translucent. You'll know it's ready when the rice pulls away slightly from the sides of the pan and has a delicate, almost jelly-like consistency. Let it cool for 5 minutes before handling—this prevents sticking when you shape the balls.

Lightly wet your hands with vegetable oil to prevent sticking. Take about 1 tablespoon of the cooled rice and flatten it into a thin circle on your palm. Place ½ teaspoon of the sweet filling mixture in the center, then gently fold the rice over the filling to completely enclose it. Roll between your palms to form a smooth, round ball about 1 inch in diameter.

Here's the thing—don't worry if they're not perfect. The beauty of these rice balls lies in their rustic charm. If the filling shows through slightly, that's actually a good sign—it means your rice is tender enough to let the sweet flavors peek through. Set the shaped balls on a plate and cover with a damp towel to prevent drying while you prepare the broth.

In a separate pot, combine the 4 cups dashi broth, 0.5 cup soy sauce, 1 tablespoon white miso paste, and 1 tablespoon grated fresh ginger. Bring to a gentle simmer over medium heat, stirring occasionally to dissolve the miso completely. Let it cook for 5-7 minutes until the flavors meld together and the broth becomes fragrant.

Taste and adjust the seasoning—you want a balance of sweetness from the sugar in the filling, umami from the miso and dashi, and a touch of ginger's zesty brightness. If it needs more depth, add a splash of soy sauce. If it's too strong, thin it slightly with 2 tablespoons hot water. The broth should coat the back of a spoon but remain light enough to let the rice balls float.

Bring the broth back to a gentle simmer, then carefully add the rice balls. Let them cook for just 2-3 minutes—enough time to warm through and develop a slight sheen from the hot liquid, but not so long they fall apart. Ladle the hot broth into bowls, placing 2 rice balls in each serving.

Here's where the magic happens: as the rice balls sit in the warm broth, they'll soften slightly and release their sweet filling into the soup, creating a harmonious blend of textures and flavors. Garnish each bowl with a sprinkle of additional grated ginger for a bright finish. Serve immediately while the broth is steaming and the rice balls are still warm and tender—this is when they're at their absolute best!

Dietary considerations for this recipe

Gluten-Free Adaptations

Traditional rice ball soup uses glutinous rice, which is naturally gluten-free, but some store-bought fillings or broths might contain hidden gluten. For a fully gluten-free version, use certified gluten-free red bean paste like Hana Saku's or make your own with mashed sweet potatoes and a touch of cornstarch.

Also, swap regular soy sauce for tamari in the broth. I've tested this version, and it holds together just as well—no one will guess it's gluten-free! 🌱

Vegan-Friendly Swaps

This recipe is already vegan-friendly when you use plant-based ingredients, but there are a few key swaps to ensure maximum flavor. Replace the dashi broth with a vegan version using kombu and shiitake mushrooms, or use a store-bought vegan dashi like Hondashi Vegan.

For the filling, ensure your red bean paste is vegan (many are), and use maple syrup instead of granulated sugar. The chestnuts can stay as-is, but if you want extra richness, add a spoonful of coconut cream to the broth. Trust me, it's just as comforting! 🌿

Lower Sugar Options

If you're watching your sugar intake, you can still enjoy this dish with a few clever adjustments. Reduce the granulated sugar in the filling to 2 tablespoons and sweeten the broth with just 1 tablespoon honey or maple syrup instead of ¼ cup.

For the filling, use unsweetened applesauce or mashed banana mixed with a pinch of cinnamon—it adds natural sweetness without spiking your blood sugar. The rice balls will still be delicious, just with a more balanced flavor profile. I promise, it's still worth making! 🍯

Nut-Free Fillings

Chestnuts are a classic filling, but if you're avoiding nuts, there are plenty of alternatives that work just as well. Try using mashed roasted sweet potatoes or diced steamed apples mixed with a bit of cornstarch to bind.

For extra flavor, add a pinch of cinnamon or cardamom to the filling. I once made a version with mashed pumpkin and a splash of vanilla extract—it was a hit with everyone, even my nut-allergic friends. The texture stays soft and the sweetness shines through! 🎃

Dairy-Free Considerations

This recipe doesn't typically contain dairy, but if you're making it for someone with dairy sensitivities, double-check all ingredients. Some store-bought red bean pastes might contain whey or other dairy additives, so opt for a homemade version or a brand like Marukyu, which is usually dairy-free.

The broth is naturally dairy-free as long as you avoid any miso pastes with dairy additives (most are, but always check labels). The only potential issue is if you're adding a dairy-based garnish, like whipped cream, but the soup itself is perfectly safe! 🥛

Kid-Friendly Tweaks

Kids often love the sweetness of this soup, but you can make it even more appealing to picky eaters with a few simple adjustments. Use chocolate-hazelnut spread (like Nutella) mixed with a bit of cornstarch for the filling—it's a hit with my nephew!

For the broth, add a splash of vanilla extract or a pinch of cinnamon to enhance the sweetness. You can also serve the rice balls plain on the side if your little ones prefer to dip them in the broth.

It's a fun way to get them excited about trying new flavors! 🍫

Frequently asked questions