Chicken, Olive, and Mushroom Orecchiette

Ingredients

• • 3/4 lb (375 g) orecchiette (or other short pasta)
  • 1 lb (454 g) white button mushrooms, thinly sliced
  • 1 onion, finely chopped
  • 1/4 cup (60 ml) olive oil
  • 2 cloves garlic, finely chopped
  • 1/2 teaspoon (2.5 ml) crushed red pepper flakes
  • 1/2 teaspoon (2.5 ml) chopped fresh rosemary
  • 2 cups (500 ml) chicken broth
  • 1/4 cup (60 ml) pitted black olives, quartered
  • 11/2 cups (375 ml) diced cooked chicken
  • 3/4 cup (180 ml) grated Parmigiano-Reggiano cheese
  • 2 tablespoons (30 ml) chopped fresh chives
  • 2 tablespoons (30 ml) butter (optional)
  • Salt and pepper