Ever wonder what to do with bonito flakes that have been used to make dashi? Feels like a waste to throw them away, doesn’t it? The good news is you can reuse them to make a delicious topping for rice or a stuffing for onigiri with this super easy recipe!

bonito flakes in a bowl

I have a confession to make – I used to throw away bonito flakes after using them to make dashi.

It felt like a huge waste and I felt guilty for doing it, but I honestly didn’t know what else to do with them. I thought that because I couldn’t reuse them to make more dashi, they didn’t serve much of a purpose anymore.

That is, until a couple of years ago when my mother scolded me for throwing them out and showed me a neat little trick to save those lovely fish flakes.

It turns out that pan frying wet bonito flakes removes the moisture and returns them to their original light and flaky texture! Add a drizzle of soy sauce, a little sugar, and sake, and you have another delicious topping for your rice! You can also make a quick furikake which is also really yummy.

So the next time you find yourself with used bonito flakes and can’t think of a way to recycle them, give this recipe a try – I promise you will love it.

used bonito flakes

What Are Bonito Flakes?

Bonito flakes, or katsuobushi (鰹節), are made from skipjack tuna or bonito that have been fermented and dried into blocks and then shaved into flakes.

They are a staple ingredient in Japanese cooking and are used to make soup stocks, sauces, salad dressings, rice toppings, and can also be used in salads, or as a garnish for several other Japanese dishes.

The Best Way to Make This Recipe

Make sure that the used bonito flakes have been squeezed thoroughly before you use them. The less water they contain and the more successful this recipe will be. That’s because we are going to dry the fish flakes in a pan so they are not soggy and limp.

When adding the wet flakes the pan, break up the lumps as much as you can. This helps remove the moisture faster and gives the flakes a light, almost crispy texture.

squeezing bonito flakes

Ingredients for Soy Sesame Bonito Flakes

Scroll all the way down for the full recipe.

  • Bonito flakes: You can use used or fresh bonito flakes to make this recipe. If you are using fresh flakes, use only 20 grams instead of 30.
  • Soy sauce: Regular or light soy sauce will work to add umami and earthiness to the fish flakes.
  • Mirin: A little mirin to balance the saltiness of the soy sauce and give the dish more depth of flavor.
  • Sake: A little sake for some sweetness and fruitiness.
  • Sugar: I’m only using a teaspoon to infuse the flakes with sweetness, but feel free to add an additional teaspoon if you prefer it sweeter.
  • Sesame seeds: Sesame seeds add nuttiness and a delicious crunch to the dish.
pan frying bonito flakes

How to Make Soy Sesame Bonito Flakes

  1. Gather all of your kitchen tools and ingredients.
  2. Add the soy sauce, sake, mirin, and sugar to a medium size skillet and turn the heat to medium low.
  3. Stir until the sugar has melted and add the bonito flakes to the pan by separating them as much as possible.
  4. Stir and toss constantly for 10 minutes to coat the flakes with the sauce, evenly.
  5. Add the sesame seeds, stir, and toss constantly for an additional 2 minutes.
  6. Turn the heat off and transfer the bonito flakes to a bowl. Serve on top of rice.


  • Add chopped scallions just before serving to add some crunch and a refreshing taste.
  • Toss in a little ichimi before serving to add some heat.
  • Add chopped dried sardines for a mineral and slightly fishy taste.
  • If you are using it for onigiri filling, add a drop of toasted sesame oil for extra nuttiness.
cooking with bonito flakes

How to Serve Soy Sesame Bonito Flakes (Katsuobushi)

As previously mentioned, this recipe is delicious over a simple bowl of Japanese rice and makes a great filling for onigiri (Japanese rice balls). It’s also good as a topping for tofu, chicken, or beef, or mixed with wafu (Japanese style) pasta.

If you enjoyed this recipe, here are other quick and easy Japanese dishes you might like:

Did you like this Soy Sesame Crispy Bonito Flakes Recipe? Are there changes you made that you would like to share? Share your tips and recommendations in the comments section below!


Soy Sesame Bonito Flakes

An easy and delicious rice topping or onigiri filling made with used bonito flakes.

  • Author: Caroline Phelps
  • Prep Time: 5 minutes
  • Cook Time: 12 minutes
  • Total Time: 17 minutes
  • Yield: about 2 cups 1x
  • Category: Seasoning
  • Method: Pan frying
  • Cuisine: Japanese
  • Diet: Low Calorie


  • 2 tablespoons soy sauce
  • 1 tablespoon sake or cooking sake
  • 1 tablespoon mirin
  • 1 teaspoon sugar
  • 3035g used bonito flakes with excess water squeezed thoroughly, or 20g fresh bonito flakes
  • 1 teaspoon sesame seeds


  1. Add the soy sauce, sake, mirin, and sugar to a medium size skillet and turn the heat to medium low.
  2. When the sugar has melted, add the bonito flakes by breaking up the lump of wet fish flakes as much as you can and tossing them with chopsticks.
  3. Keep tossing the bonito flakes for 10 minutes until they separate and dry out.
  4. Add the sesame seeds and cook for an additional 2 minutes, tossing constantly. Turn the heat off and serve over rice.


To store, transfer the bonito flakes to an airtight storage container and refrigerate for up to 1 month.

Keywords: topping, filling, seasoning

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