Have you've ever wondered if you can use your leftover kombu after making dashi? Well, the answer is, you can! In fact, you won't believe how delicious kombu can be until you try this recipe. This umami packed simmered kelp called "tsukudani" is one of the most popular onigiri fillings in Japan!
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What is "onigiri"?
An onigiri (おにぎり) is a popular Japanese rice ball, most commonly shaped into a triangle or cylinder and then wrapped with a thin sheet of dry seaweed called "nori".
They were also traditionally known as "omusubi" (お結び) or "nigirimeshi" (握り飯) but those words are not commonly used now, and if you do see them, it's more likely to be in writing rather than spoken.
Onigiri are eaten with hands (no chopsticks or spoon) and commonly seen in bento boxes. They're a popular option of lunch, it's kinda like a rice equivalent to a sandwich after all!
Onigiri can be made with just plain salted rice, but actually they come in all kinds of different flavours! Fish, meat, vegetables, you name it! The sky's the limit when it comes to onigiri. Not only are they highly customizable, but also portable and convenient for when you're on the go!
Here's a few popular flavours that you might see in Japan
- Salmon (鮭)
- Seasoned cod roe (辛子明太子)
- Hard cod roe (たらこ)
- Ume pickled plum (梅)
- Seasoned kombu seaweed (昆布)
- Tuna mayo (ツナマヨネーズ)
- Seasoned bonito flakes (おかか)
Today I'm going to show you how to make kombu onigiri, it's one of the top 5 onigiri flavours in Japan!
What is kombu?
Kombu is a type of dried edible kelp and an essential ingredient in Japanese cooking. It's most common use is in "dashi", a soup stock that helps add umami and authentic Japanese flavour to dishes.
To make dashi, kombu is simply soaked until it's rehydrated and then heated up. I usually remove the kombu just before the water starts to boil as boiling kombu can release a bitter flavour into the dashi. Dashi is commonly used in miso soup, noodle broths and hot pot dishes.
After the kombu is removed from the dashi, there's no need to throw it away! You can use it to make this delicious tsukudani!
I use Hidaka Kombu for this recipe after using it to make dashi.
What is Tsukudani (佃煮)
Tsukudani is a traditional type of Japanese preserved food that has been simmered in a sweet and salty broth, most commonly made from soy sauce and sugars.
It can be made with fish, meat or vegetables, but I've gotta say that the umami from the kelp makes kombu tsukudani my favourite!
Since the broth is simmered down completely, the flavour is strong and concentrated. It's not really something you'd eat by itself, but it's the perfect accompaniment for rice, and the perfect onigiri filling!
Preparing Kombu for Tsukudani
It's best to use left over kombu for this dish. So after you've made dashi, don't throw the kombu away. You can either make tsukudani straight away, or save the kombu in the freezer for when you have time.
If you want to start with dried kombu, I recommend soaking it in water over night before use. The water will become dashi and you can store it in the fridge for another recipe.
The kombu takes a while to soften so I add 1 tsp of rice vinegar and 2 tbsp of sake to the water at the beginning. These additions help soften the kombu quickly.
In the case that you finish the recipe but the kombu is still a bit hard, you can return it to the pan, add more water and simmer it down until the water is gone. The tsukudani won't lose flavour because you'll evaporate the water down, repeat until you achieve the desired softness.
Kombu is the perfect onigiri filling or topping with rice! If you have leftover kombu tsukudani, you can keep it in the fridge for 2-3 weeks.Print