- 6 1/2 tablespoons olive oil
- 10 ounces shiitake mushrooms, stems removed and caps sliced thin
- 2 1/4 teaspoons salt
- 1/4 teaspoon fresh-ground black pepper
- 1 large onion, chopped
- 1 quart water
- 1 quart canned low-sodium chicken broth or homemade stock
- 1/3 cup long-grain rice
- 2 pounds asparagus, tough ends snapped off and discarded, spears cut into 1-inch pieces
- 16 slices (1/2-inch thick) baguette
- 1/4 pound Gruyere, shredded
- In a large pot, heat 2 tablespoons of the oil over moderately high heat. Add the mushrooms, 1/4 teaspoon of the salt, and the pepper and cook, stirring occasionally, until the mushrooms are golden, about 5 minutes. Remove the mushrooms from the pot and set aside. Reduce the heat to moderately low and add another 11/2 tablespoons of the oil to the pot. Add the onion and cook, stirring occasionally, until translucent, about 5 minutes.
- Add the water, broth, rice, and the remaining 2 teaspoons of salt to the pot. Bring to a boil. Continue boiling for 10 minutes, stirring occasionally. Add the asparagus. Cook until the asparagus is tender, about 5 minutes.
- In a blender or food processor, puree the soup until completely smooth. Return the soup to the pot and stir in the reserved mushrooms.
- Meanwhile, heat the broiler. Put the bread on a baking sheet and brush both sides of the bread with the remaining 3 tablespoons of oil. Broil the bread until brown, about 2 minutes. Turn and top with the Gruyere. Broil until the cheese melts, about 2 minutes longer.
- Reheat the soup if necessary. Serve topped with the Gruyere croutes.