Onigiri is an indispensable addition to the Japanese bento lunch box. Its deliciousness not only stems from the seasoned sushi rice or the nori sheets but also from its yummy fillings.
If you have tried these Japanese rice balls, you will notice there are endless options for onigiri fillings. Thus, there may be times you have no clue what to choose.
To help you overcome the weariness of sampling the same onigiri fillings, such as tuna or salmon, I have compiled this list of 14 fillings ideas to spice up your Japanese rice balls with fresh and intriguing flavors!
Without further ado, let’s start now!
Brief Overview On Onigiri
Also known as omusubi, onigiri are iconic Japanese rice balls with wonderful tastes, akin to sandwiches. They feature seasoned steamed rice (Japonica short rice, short-grained rice) wrapped in dried seaweed (nori) and stuffed with savory contents.
Typically, onigiri utilizes salmon or tuna for the fillings. However, there are more filling ideas to try than you think, both carnivore and vegetarian. I will cover them in the following section.
Local people often enjoy onigiri as portable snacks or quick lunches. You can buy this staple in convenience shops and grocery stores or make it at home effortlessly.
Different Onigiri Forms
Thanks to the use of a mold, onigiri can take on various forms. The most prevalent ones include:
- Triangular onigiri (resembling a mountain shape).
- Round onigiri.
- Cylindrical onigiri (also known as tawara, meaning rice bales)).
- Free-form onigiri (character-based or animal shapes).
Historians believe onigiri started in ancient times, specifically the Yayoi era (300 BC – 300 AD). Its initial form includes mainly steamed and grilled rice.
Onigiri’s reign began during the Edo period (1603 – 1868) when the Japanese adopted the concept of wrapping rice in seaweed to prevent sticky fingers while on the go.
Both names (onigiri, omusubi) comprise two separate parts: the honorific prefix “o” and the main terms. If “nigiri” means “to grasp”, “musubi” translates as “to bind”.
10 Hearty Carnivore Onigiri Fillings
Let’s kick off my list of onigiri fillings ideas with some popular carnivore options.
1. Tuna Mayo
The combination of tuna and mayonnaise in onigiri is a classic, humorously referred to as “chicken of the sea”. This filling is affordable and quick to prepare. All you need to do is drain tuna from a can and blend it with creamy Japanese mayonnaise.
Unlike American mayonnaise, which utilizes whole eggs, Japanese mayonnaise uses egg yolks only for a more yellowish color, custardy texture, and richer taste. Regarding the fish, you can use raw, sushi-grade tuna or grill shredded tuna.
Although basic, this filling provides excellent flavors to complement the plain rice and seaweed.
2. Sake (Grilled Salted Salmon Flakes)
Instead of tuna, you can try shredded salmon with mayonnaise for another delectable onigiri filling. In Japanese, this filling is called “sake” and is a wonderful source of vitamin D, protein, and omega-3.
Here is how to prepare sake onigiri’s filling. Simply grill salmon fillet marinated in soy sauce (or teriyaki sauce) and shred it into flakes with a fork. The salted salmon flakes provide a tart flavor to the rice surrounding them.
3. Umeboshi (Pickled Plum)
Also called pickled plum, umeboshi is a sour and salty filling that pairs nicely with Japanese steamed rice. Yet, it has an acquired taste for people unfamiliar with its pungent flavor.
You can buy umeboshi at various Asian stores or make it at home. The ingredient is not only great for enhancing metabolism and digestion but also a wonderful preservative to make the dish edible for longer periods, especially during heated summer.
4. Tarako (Salted Cod Roe)
Tarako means cod roe marinated in soy sauce, salt, and other ingredients, giving the filling a salty flavor. Its smokey texture and umami-rich taste infuse a robust caviar flavor into onigiri. To prepare tarako, simply peel away its thin membrane.
Don’t confuse tarako with mentaiko (which is right below). Both are cod roe, but tarako is not spicy.
5. Mentaiko (Spicy Cod Roe)
Like tarako, mentaiko is cod roe with an appealing melt-in-your-mouth texture. Typically, people combine seasoned mentaiko with mayonnaise before putting it on onigiri.
What sets this filling apart is its spicy flavor. However, don’t worry if you are afraid of heat. As long as you distribute this filling throughout the rice to diminish its spiciness, you are alright!
6. Katsuobushi/ Okaka (Bonito Flakes)
Also called katsuobushi or okaka, bonito flakes are an important component for creating dashi stock in Japanese cuisine. They are smoked, fermented fish fillets that will infuse your onigiri with umami.
To prepare okaka, simply mix the ingredient with soy sauce, mirin, and salt. The result works magically as a mesmerizing onigiri filling.
7. Tenmusu (Shrimp Tempura)
Shrimp tempura with sweet Tsuyu sauce as an onigiri filling is unquestionably a fail-proof choice. Its Japanese name comprises two parts: tempura and musubi (another moniker for onigiri).
Together, you will have a crispy and savory filling of shrimp tempura blending well with steamed rice balls. The combination is ideal for picnic food.
8. Ebi Mayo (Shrimp Mayonnaise)
If you need an ideal snack for upcoming potlucks, let’s apply ebi mayo for your onigiri! Preparing this filling idea is a simple three-step process: cook the shrimp, chop them into pieces, and season them with mayonnaise, salt, and pepper.
9. Karaage (Fried Chicken)
Karaage means fried chicken in Japanese. This simple filling brings crunchy textures and savory flavors to your onigiri. You can even use frozen chicken nuggets to accommodate your homemade rice balls.
Eel has an acquired taste that not everyone can enjoy. Some individuals may find its sliminess repulsive. Yet, once you are familiar with its flavor, you will love how it is ideal as an onigiri filling.
To prepare this filling, you need to grill the eel and then slice it into smaller pieces.
4 Fulfilling Vegetarian Onigiri Fillings
If you are a vegan, this section is for you. It features fulfilling vegetarian onigiri fillings that help you enjoy the Japanese staple while maintaining your vegan diet.
1. Kombu (Kelp)
The first vegan-friendly stuffing ideal for your onigiri is kombu (or kelp). The Japanese often use the tsukudani technique to prepare kombu by simmering it with soy sauce, cooking sake, mirin, and sugar.
Shredded cheese is the perfect onigiri filling when you are having a hectic schedule. The flavor mix of cheese and grains will be one of the best things you have ever tasted.
Before applying to onigiri, you should pick your favorite cheese, shred it, and combine it with salt, pepper, and cilantro.
3. Takanazuke (Pickled Mustard)
Takanazuke refers to salty, crispy, and naturally spicy Japanese mustard pickled in soy sauce. It is a delightful plant-based stuffing for not only onigiri but also spaghetti and fried rice.
4. Negi Miso (Leek And Miso Sauce)
Negi Miso is a sweet and savory miso-based sauce that comprises negi (Japanese green onion). Besides using it for marinating meat and dipping veggies, negi miso is also perfect for eating with steaming rice in onigiri.
Read More: 35 Fun and Tasty Sushi Filling Ideas
Let’s Make Your Own Onigiri!
You must be an expert on onigiri fillings right now! However, fillings are not enough for a delectable onigiri meal. Let’s continue by learning how to make your own Japanese rice balls at home!
A nice plate of homemade onigiri will require the following ingredients:
- Short-grain steamed rice.
- Dried seafood (nori).
- Sesame seeds.
- Your favorite fillings (pick one or more options).
Follow this straightforward step-by-step guide to prepare your delicious onigiri:
- Step 1: Prepare steamed rice and your favorite onigiri fillings.
- Step 2: Place steamed rice in a small bowl and season it with rice seasoning.
- Step 3: Dip your hand in water, then sprinkle salt over your hands.
- Step 4: Make a hole in the rice and add your selected fillings there.
- Step 5: Slightly fold the rice into the desired shape (typically triangular shape) using both hands. Do not squeeze it.
- Step 6: Place the rice on top of a nori sheet’s rough surface, then wrap the excess part of the sheet so that it hugs the rice.
Watch this video: Have a closer look at how to prepare onigiri from A to Z with this tutorial.
You can store onigiri by covering it in plastic wrap to prevent the rice from getting dry. It is edible after a few days in the refrigerator and up to a month in the freezer. Yet, when freezing it, make sure to unwrap the nori sheet.
FAQs About Onigiri Fillings
If you have other inquiries about onigiri fillings, you will find their answers here. This section covers top questions about the topic with brief responses.
1. Is it a must to prepare onigiri immediately before packing for lunch?
Fortunately, the answer is no. Follow the aforementioned storage hints and cover your rice balls in plastic wrap. Then, wrap the whole thing with a thick kitchen towel. With this approach, your onigiri will remain edible even when the rice becomes hard in the fridge.
2. How can I prevent onigiri from becoming wet and soggy?
To prevent wet onigiri, make sure it does not absorb water. Thus, storing it in plastic wrap is essential.
3. Should I eat onigiri hot or cold?
Both ways are great for enjoying onigiri. Yet, serving onigiri cold is a more popular approach.
What Fillings Do You Plan For Your Next Onigiri Meal?
All mentioned fillings ideas in my compilation are the most popular choices for onigiri. However, note that you can experience countless other options when preparing this staple at home.
So, is there any option that sparks your interest for the upcoming onigiri meal? If you have tried it or want to suggest other creative fillings, share your thoughts below. Thank you for reading!