1. Soak saffron in 1 tablespoon of warm water for 10 minutes to release its color and flavor.

2. In a medium saucepan, bring dashi stock to a simmer.

3. Add cilantro, dill, basil, olive oil, garlic, onion, celery, and carrots to the saucepan. Simmer for 15 minutes, or until vegetables are tender.

4. Add saffron and its soaking liquid to the saucepan.

5. Season with salt and black pepper to taste.

6. Stir in sour cream, if desired, and serve immediately.