‘Ushio-ni’ Soup with Clams, Spanish Mackerel, Field Mustard Heralds Approach of Spring

By Yasuto Akaike / Yomiuri Shimbun Staff Writer

12:30 JST, March 8, 2026

Asari clams, Spanish mackerel and nanohana greens are the three major ingredients of the ushio-ni soup cooked by Akihiko Murata, who runs a Japanese cuisine restaurant. Murata has shared a recipe for the dish that highlights the ingredients’ natural flavors. The dish’s simplicity signals the approach of spring.

Ushio-ni is a soup in which seafood is poached in broth. Sea bream is typically used, but Murata uses Spanish mackerel instead.

“The fish is rich in fat and very delicious around this time of the year,” Murata said.

Spanish mackerel is a very versatile fish that can be used in various dishes: from sashimi, in which it is eaten raw, to yuan-yaki, in which it is marinated with yuzu slices before being grilled.

During the preparation, sprinkle salt on the fish to remove its fishy odor. This step is essential as the dish uses few seasonings.

Murata said, “I prefer this approach, as it keeps as much of the umami of the fish as possible.” Blanching in very hot water also works.

Blanching the nanohana greens by briefly immersing it in boiling water keeps the green color vibrant. Cooling without plunging it in water prevents the loss of flavor. This technique is called “oka-age.”

The skin of Spanish mackerel is soft and prone to sticking to bottom of the pot, so cook it skin-side up. This preserves the skin’s beautiful silver sheen, adding visual appeal when eating.

This dish does not use kombu seaweed or dashi stock. But the use of clams works very effectively as they provide plenty of umami and saltiness.

“If you prefer a lighter flavor, you don’t need to add salt,” Murata said.

After poaching the Spanish mackerel, add the clams. Then, add the blanched nanohana greens to let it absorb the broth.

To finish, add half a teaspoon of sesame oil. Its aroma softly spreads the moment it is added. The effect is similar to drizzling olive oil over Italian dishes at the end of cooking.

When the dish was served, I tasted the Spanish mackerel first. A gentle mouthfeel was followed by a robust umami. Next, I enjoyed the slightly chewy texture of the plump clams, then was refreshed by the field mustard.

I could not stop eating the delicious trio, each with a different texture and flavor, like an endless cycle. I was captivated by the deep, complex flavors drawn out from the ingredients.

Ushio-ni of clams and Spanish mackerel

Ingredients (serves 4):

• 200 grams asari clams
• 200 grams Spanish mackerel fillet
• 1/2 bunch nanohana greens (80 grams)
• 1/2 tsp light soy sauce
• yuzu zest
• 1/2 tsp sesame oil
• 3 tbsp sake



Directions:

1. Purge sand from the clams. Cut the Spanish mackerel into four pieces, lightly sprinkle salt on both sides and let sit for about 10 minutes.

2. Cut the nanohana greens into 5-centimeter lengths. Bring water to a boil in a pot and blanch the nanohana greens for about 30 seconds. Drain in a colander.

3. Pat the Spanish mackerel pieces dry with paper towel.

4. In a separate pot, heat 250 milliliters of water with the sake. When it comes to a boil, add the Spanish mackerel pieces, skin-side up. Cover and poach over medium-low heat for 3 minutes.

5. Add the clams and cover. Once the shells open, add 1/3 teaspoon of salt and the soy sauce.

6. Add the nanohana greens and let it absorb the broth. Add the sesame oil to flavor the dish.

7. Serve in a bowl and top with yuzu zest.

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  Blanch the nanohana greens.

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  Pat the Spanish mackerel dry with paper towel.

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  Poach the Spanish mackerel pieces skin-side up.

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  Add the clams.

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