Mushroom and Chicken Risotto

Ingredients

• 2 tablespoons butter
• 1/2 pound mushrooms, cut into thin slices
• 2/3 pound boneless, skinless chicken breasts (about 2), cut into 1/2-inch pieces
• 1 teaspoon salt
• 1/4 teaspoon fresh-ground black pepper
• 5 1/2 cups canned low-sodium chicken broth or homemade stock, more if needed
• 1 tablespoon cooking oil
• 1/2 cup chopped onion
• 1 1/2 cups arborio rice
• 1/2 cup dry white wine
• 1/2 cup grated Parmesan cheese, plus more for serving
• 2 tablespoons chopped fresh parsley