Bonito flakes, or katsuobushi, are thin shavings of dried, smoked and fermented skipjack tuna. They are intensely savoury, and they make up half of the classic dashi stock, with kombu as the other half.
Where to find them
Japanese grocers stock the widest range, including large packs and shaved flakes. Some larger supermarkets sell a small pack in the Japanese section. Online shops are the easiest option for bigger packs.
How to make dashi with them
Add a generous handful of flakes to hot water that has just come off the boil. Leave them for a minute or two, then strain them out. Do not boil the flakes, since that makes the stock bitter.
Other ways to use them
Sprinkle a few flakes over warm tofu with soy sauce. Use them as a topping for okonomiyaki. Stir them into rice or noodle dishes for a smoky savoury note.
Storage
Keep the packet sealed in a cool, dry place. Once open, the flakes lose their smell over time, so use them within a few months.
For a stock that uses them, read our dashi guide. For a simpler route to the stock, see our dashi bags guide. For the seaweed half of the pair, read our kombu guide.