Farro with Brie and Squash

Name: Farro with Brie and Squash
Ingredients: 2 red onions; 3 tablespoons extra-virgin olive oil, plus more for drizzling; 8 ounces sliced cremini mushrooms; 2 teaspoons chopped fresh thyme; Kosher salt and freshly ground pepper; 1 1/3 cups farro; 1/4 cup dry white wine; 1 pound cubed peeled butternut squash (about 4 cups); 3 ounces brie cheese, rind removed and cubed, plus thin slices for topping; 1/2 cup chopped fresh parsley