
Like many of you, I want to try to eat better and cook healthier meals for my family this year. Instead of red meat, we start to eat more fish since it has less saturated fat and cholesterol. One of our favorite fish recipes is Grilled Mackerel. Packed with omega-3 fatty acid, vitamin D, protein and potassium, mackerel is a great choice of fish to include in our diet. This grilled mackerel recipe is extremely easy to make and the only seasoning that I used was shio koji (塩麴), a versatile ingredient in Japanese cooking.
If you’re new to shio koji, you can read more about this magical ingredient on this page about shio koji.

Grilled Mackerel With Shio Koji
Now that you’ve learnt about shio koji, let’s talk about this quick and easy mackerel dish.
If you frequent Japanese restaurants, you’ve probably seen or tried Saba Shioyaki, or Grilled Mackerel. Saba shioyaki is mackerel seasoned with salt and grilled until the skin is crispy and the flesh is tender. It is sometimes included in bento lunch boxes as well.
Since shio koji is rice koji that has been fermented with sea salt, I thought I would just swap salt with shio koji to make Grilled Mackerel. As I expected, the enzyme in shio koji brought out the umami (or richness – one of five basic tastes) of the fish and the result was simply amazing!!!
The healthy oil from the fish gave it a nice crispy exterior. And the flesh was very tender and flavorful. With a beautiful char from the crispy mackerel skin, this simple fish dish is ready in minutes.
Make your own shio koji

In case you are not able to find shio koji in your local Japanese supermarkets, I made this video tutorial for you to make your own shio koji. Koji is slightly easier to find than shio koji, so I hope you make your own shio koji to enjoy my shio koji recipes.
For a step-by-step recipe for Homemade Shio Koji, click here.

Grilled Mackerel with Shio Koji
Ingredients
- 5.3 oz mackerel (2 pieces)
- 2 Tbsp shio koji (I used Hikari Miso Shio Koji; you can substitute with 2 tsp kosher salt, but it will lack in umami)
- lemon wedges
Instructions
- Before You Start…Please note that this recipe requires 30 minutes of marinating time.
- In a flat container, put 5.3 oz mackerel and 2 Tbsp shio koji together and marinate for at least 30 minutes. You can adjust the marinating time according to the size of your mackerel fillets.
To Broil (recommended)
- Preheat the broiler* with a rack placed about 6 inches (15 cm) away from the top heating element (in the middle) for 3 minutes. Line a baking sheet with foil for easy cleaning (brush the foil with some oil so the skin doesn‘t stick to it). Place the fish on the foil, skin side down. Broil it on Medium/High for 15–20 minutes, until the surface is blistered and browned a bit. You do not need to flip it. *Typical broiler settings: Low 450ºF/232ºC, Medium 500ºF/260ºC, and High 550ºF/288ºC.
To Bake (optional)
- Preheat the oven to 425°F (218ºC) with a rack placed in the middle. For a convection oven, reduce cooking temperature by 25ºF (15ºC). Bake the fish on parchment paper for 20–25 minutes until golden brown, opaque, and flaky.
To Serve
- Serve immediately with lemon wedges.
To Store
- You can keep the leftovers in an airtight container and store in the refrigerator for up to 2 days.
Nutrition
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