You guys know I love onigirazu (aka sushi sandwich) recipes, and this is my autumn version. With a nutmeg cinnamon steamed butternut squash and sesame garlic spinach filling, this Autumn Onigirazu a stunning take on a Japanese sushi sandwich.

Onigirazu is a Japanese rice sandwich, essentially a modern twist on the traditional onigiri (rice ball). The name "onigirazu" comes from the word "nigirazu," meaning "without shaping or squeezing," which refers to the way the rice and ingredients are assembled rather than tightly molded into a ball.
Unlike onigiri, which is pressed into a triangular or round shape, onigirazu is made by layering ingredients on top of rice placed on a square sheet of nori (seaweed) and then folding the nori around the filling, creating a sandwich-like package. It is easy to make and allows for a wide range of fillings, from traditional Japanese flavours like pickled plum, grilled salmon, or tamagoyaki (Japanese rolled omelette), to more modern ingredients like fried chicken, avocado, or even American-style fillings.
If you're a fan of sushi sandwiches, then you'll love my more authentic onigirazu recipe using tuna or my katsu onigirazu inspired by fried chicken flavours!
Why I love this recipe
Simple: We're making sushi rice and creating two elements for the filling. Once you've made it, you can eat it throughout the week for lunch or dinner, or a snack!
Portable: Because we're making a sushi-style sandwich, you can easily take it with you to work, on a trip, and it will stay in tact.
Customisable: Although we've made the filling using butternut squash and spinach, you can prepare so many different fillings. I provide some alternatives further down this blog!
If you're a fan of Japanese-inspired food, then you'll love my oyaki dumplings that are super simple to make and absolutely delicious, or my tamago harissa sando which is an egg sandwich seasoned with harissa...a favourite of mine!
Ingredients and Substitutions
Sushi rice: A short-grain sushi rice is perfect for this recipe. It'll be sticky and warm in flavour, perfect when seasoned with rice wine vinegar, sugar, and salt. You could also use brown sushi rice.
Butternut squash: For an autumnal filling, we're using butternut squash. If you don't have this, you could use any squash, pumpkin, or sweet potato that's accessible to you.
Ginger: Fresh ginger is best. You can use ground ginger if that's all you've got. I'd recommend ¼ tsp.
Nutmeg: Ground nutmeg adds a lovely autumnal flavour.
Cinnamon: Ground cinnamon provides a warmth to the butternut squash.
Salt: I always use Malden salt for my recipes.
Soy sauce: Light soy sauce is the option you want. Dark soy sauce is higher in sodium and darker in colour, you don't want to use this variety.
Spinach: Fresh spinach that you wilt down. If you don't have spinach, you could use any other leafy green that you steam to wilt down.
Garlic: Fresh garlic cloves, finely minced. You can always use garlic granules if you fancy.
Sesame oil: For a nutty flavour. If you're allergic or don't have sesame oil, then a nut oil like peanut oil or walnut oil would be really nice.
Sugar: For a bit of sweetness, I use white caster sugar. You could also use honey.
Mayonnaise: To add creaminess. You could also use kewpie mayonnaise or sour cream.
Sriracha: For spice. You could use chili oil if you don't have sriracha.
Nori: Seaweed sheets are an essential part of this recipe. You can get them from most supermarkets in their Asian section.
Step by step instructions with photos
Step 1: Pour your sushi rice into a saucepan and rinse with water. Drain the rice then add in the same volume of water as rice (300g). Place a lid on the pan and onto medium heat. When the water is bubbling, reduce the heat to low and set a timer for 10 minutes. Don't remove the lid. Once the 10 minutes has gone by, turn the heat off and leave for another 10 minutes.
Step 2: While your rice is cooking, place your butternut squash slices skin up into a steamer. Cook for 15-20 minutes on medium heat until the butternut squash is soft. Keep an eye on the water level as you might need to top it up otherwise it'll evaporate and burn the pan.
Step 3: Once your rice is cooked and fluffy, combine the rice wine vinegar, sugar, salt, and boiling water in a small bowl, give it a stir, then pour it into your rice. Give everything a good mixture, then leave to cool.
Step 4: Your butternut squash is ready when it's soft and buttery. Remove the squash from the peel using a spoon and place it into a separate bowl. Keep 2 tablespoons of the butternut squash in a separate small bowl for the dipping sauce.
Step 5: To your butternut squash, add minced ginger, nutmeg, cinnamon, MSG (or sugar), and light soy sauce. Give it all a good mix, taste and season according to your preferences.
Step 6: Place your spinach in a colander and in the sink, pour boiling water gently over the spinach. You'll slowly see it begin to wilt. Once fully wilted, strain and roughly chop. Add to a bowl with minced garlic, sesame oil, sugar, and salt. Give it a good mix then set it aside.
Step 7: To make the dipping sauce, get the remaining butternut squash and then add to it sriracha, mayonnaise, and light soy sauce. Give it a good mix and then set aside.
Step 8: Once your rice has cooled, time to assemble your onigirazu. Place a sheet of nori onto a clean surface with a flat side of the square facing you. Place sushi rice into the centre of the nori sheet and form into a square around 4 inches in diameter and ½ inch thick. Top with spinach, butternut squash, and more rice. Take another nori sheet and slice it into a 5 inch by 5 inch square. Place it on top of the sushi rice. Brush the edges of the bottom nori sheet with rice wine vinegar. Then once slightly moist, wrap up and seal.
Step 9: Wrap with clingfilm or a non-plastic alternative and form into a square. Place in the fridge for a minimum of 15 minutes and enjoy!
What to do with leftovers
Storage: Place any autumn onigirazu in the fridge for up to 3 days. Any filling or rice leftovers, place them all into a bowl with the dipping sauce and combine. Eat as a meal or with nori sheet.
Freezing: Yes, you can freeze these onigirazu sushi sandwiches. Place them in clingfilm and into the freezer for up to 3 months. Leave to thaw in the fridge overnight before eating them. Their texture may change slightly.
FAQs
You could add sliced avocado, omelette, sliced cucumber, pickled radish, fresh sliced salmon, sliced marinated tofu, the options are endless!
I love eating sushi sandwiches with stir fried vegetables. You could also serve it with ramen.
If you don't let the rice cool, it will heat up the nori sheet, breaking it down slightly and changing the texture of it. Ensuring the rice is cool makes for a crisp and fresh nori sushi sandwich.
Other related recipes!
If you tried this Baked Chicken with Cream of Chicken Soup or any other recipe on my website, please leave a 🌟 star rating and let me know how it went in the 📝 comments below. Thank you!
Autumn Onigirazu
Ingredients
For the rice
- 300g sushi rice
- 2 tablespoon rice wine vinegar
- ½ tablespoon sugar
- 1 teaspoon salt
- 1 tablespoon boiling water
For the butternut squash filling
- 1 small butternut squash slice off top and bottom, slice in half lengthways and then down the middle. Scoop out the seeds.
- ½ inch ginger minced
- ⅛ teaspoon ground nutmeg
- ⅛ teaspoon ground cinnamon
- ⅛ teaspoon MSG or sugar
- 2 teaspoon light soy sauce
For the spinach filling
- 200g fresh spinach
- 1 garlic clove minced
- ½ teaspoon sugar
- ½ teaspoon salt
- ½ tablespoon sesame oil
For the dipping sauce
- 2 tablespoon cooked butternut squash from above
- 1 tablespoon sriracha
- 1 tablespoon mayonnaise
- 1 tablespoon light soy sauce
For assembly
- 8 nori sheets
- rice wine vinegar for brushing the edges
Instructions
- Pour your sushi rice into a saucepan and rinse with water. Drain the rice then add in the same volume of water as rice (300g). Place a lid on the pan and onto medium heat. When the water is bubbling, reduce the heat to low and set a timer for 10 minutes. Don't remove the lid. Once the 10 minutes has gone by, turn the heat off and leave for another 10 minutes.
- While your rice is cooking, place your butternut squash slices skin up into a steamer (see images further up in the blog for reference). Cook for 15-20 minutes on medium heat until the butternut squash is soft (spike with a fork to check). Keep an eye on the water level as you might need to top it up otherwise it'll evaporate and burn the pan.
- Once your rice is cooked and fluffy, combine the rice wine vinegar, sugar, salt, and boiling water in a small bowl, give it a stir, then pour it into your rice. Give everything a good mixture, then leave to cool (I place it into the fridge).
- Your butternut squash is ready when it's soft and buttery. Remove the squash from the peel using a spoon and place it into a separate bowl. Keep 2 tablespoons of the butternut squash in a separate small bowl for the dipping sauce.
- To your larger bowl of butternut squash, add minced ginger, nutmeg, cinnamon, MSG (or sugar), and light soy sauce. Give it all a good mix, taste and season according to your preferences.
- Place your spinach in a colander and in the sink, pour boiling water gently over the spinach. You'll slowly see it begin to wilt. Once fully wilted, strain out any excess liquid and roughly chop. Add to a bowl with minced garlic, sesame oil, sugar, and salt. Give it a good mix then set it aside.
- To make the dipping sauce, get the remaining butternut squash and then add to it sriracha, mayonnaise, and light soy sauce. Give it a good mix and then set aside.
- Once your rice has cooled, time to assemble your onigirazu. Place a sheet of nori onto a clean surface with a flat side of the square facing you. Place sushi rice into the centre of the nori sheet and form into a square around 4 inches in diameter and ½ inch thick. Top with spinach, butternut squash, and more rice. Take another nori sheet and slice it into a 5 inch by 5 inch square. Place it on top of the sushi rice. Brush the edges of the bottom nori sheet with rice wine vinegar. Then once slightly moist, wrap up and seal.
- Wrap with clingfilm or a non-plastic alternative and form into a square. Place in the fridge for a minimum of 15 minutes and enjoy!
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