Simmered Seaweed and Tofu Soup with Bonito Broth

By AislePrompt Editorial · Published 2026-05-11 · Updated 2026-05-11

A light and nourishing Okinawan soup featuring tender seaweed and silky tofu in a savory bonito-infused broth. This Japanese-inspired soup recipe, ready in about 50 minutes, pairs dried kombu seaweed, bonito flakes, soft tofu for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 90 calories and feeds 3, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 10g dried kombu seaweed
• 15g bonito flakes
• 200g, cut into 1-inch cubes soft tofu
• 6 cups water
• 1 tbsp soy sauce
• 1/2 tsp salt
• 1 stalk, thinly sliced green onions

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Instructions

1. Step 1: Soak 10g dried kombu seaweed in 6 cups cold water for 30 minutes to soften, then gently bring to a simmer over medium heat, removing the kombu just before the water boils.
2. Step 2: Add 15g bonito flakes to the simmering water and cook for 2 minutes, then strain the broth through a fine sieve to remove the flakes.
3. Step 3: Return the clear broth to the pot and gently add 200g soft tofu cubed, simmering for 5 minutes until warmed through.
4. Step 4: Season the soup with 1 tbsp soy sauce and 1/2 tsp salt, tasting to adjust seasoning.
5. Step 5: Ladle soup into bowls and garnish with 1 thinly sliced green onion stalk before serving.