- 5 cups chicken broth (40 fluid ounces)
- 1 cup water
- 1 pound thin to medium asparagus, trimmed and cut into 1/4-inch-thick slices, leaving tips 1 1/2 inches long
- 1 tablespoon olive oil
- 1/2 stick (1/4 cup) unsalted butter
- 3/4 pound fresh shiitake mushrooms, stems discarded and caps cut into 1/4-inch-thick slices
- 1 small onion, finely chopped
- 1 1/2 cups Arborio rice (10 ounces)
- 1/2 cup dry white wine
- 2 ounces Parmigiano-Reggiano (1 cup)
- Bring broth and water to a boil in a 4-quart pot. Add asparagus and cook, uncovered, until crisp-tender, 3 to 4 minutes. Transfer asparagus with a slotted spoon to a large bowl of ice and cold water to stop cooking, then drain and pat dry. Keep broth at a bare simmer, covered.
- Heat oil with 1 tablespoon butter in a 4-quart heavy saucepan over moderately high heat until foam subsides, then sauté mushrooms, stirring occasionally, until browned, about 4 minutes. Season with salt and pepper, then transfer to a bowl.
- Cook onion in 2 tablespoons butter in saucepan over moderate heat, stirring, until softened, about 3 minutes. Add rice and cook, stirring, 1 minute. Add wine and cook, stirring, until absorbed, about 1 minute.
- Ladle in 1 cup simmering broth and cook at a strong simmer, stirring, until absorbed, about 2 minutes. Continue simmering and adding broth, about 1/2 cup at a time, stirring frequently and letting each addition be absorbed before adding next, until rice is just tender and looks creamy, 18 to 20 minutes. (Save leftover broth for thinning.)
- Remove from heat and stir in 1/2 cup cheese, remaining tablespoon butter, and salt and pepper to taste. Gently stir in asparagus and mushrooms, then cover pan and let stand 1 minute. If desired, thin risotto with some of remaining broth. Serve immediately with remaining cheese on the side.