- 4 tablespoons vegetable oil
- 12 ounces fresh shiitake mushrooms, stemmed, caps sliced
- 12 green onions, white and pale green parts thinly sliced, tops cut into 1/2-inch lengths and reserved
- 1 5-inch piece fresh ginger, peeled, thinly sliced
- 3 14 1/2-ounce cans low-salt chicken broth
- 1 cup dried porcini mushrooms* (about 3/4 ounce), rinsed briefly
- 1 6-ounce package baby spinach, thinly sliced
Heat 3 tablespoons oil in heavy large pot over medium-high heat. Add shiitake mushrooms and sauté until golden, about 5 minutes. Transfer mushrooms to medium bowl. Heat remaining 1 tablespoon oil in same pot. Add thinly sliced green onions, ginger, and garlic; sauté 1 minute. Add water, broth, and porcini. Bring to boil. Reduce heat to medium and simmer 20 minutes. Strain soup into large pot, pressing on solids in strainer to release as much liquid as possible. Discard solids in strainer. Stir shiitake mushrooms into broth. Reduce heat to medium and simmer 5 minutes. Add sugar and salt. DO AHEADCan be made 1 day ahead. Cool slightly, cover and refrigerate. Bring to simmer before continuing.
Add green onion tops and spinach to soup and simmer until spinach wilts, about 1 minute. Ladle into bowls.
* Dried porcini mushrooms are available at Italian markets, specialty foods stores and many supermarkets.