Follow these simple steps to bring this dish to life in your own kitchen:

1. Preheat your oven to 350°F (175°C) and lightly grease a 9×13-inch baking dish.
2. In a large skillet, heat a tablespoon of olive oil over medium heat. Add carrots, celery, and onions, sautéing for about 5 minutes until they begin to soften. Stir in mushrooms and garlic, cooking for an additional 3 minutes.
3. Remove the vegetables from the skillet and set aside. In the same skillet, melt the butter over medium heat, then whisk in the flour, cooking for 1-2 minutes until golden.
4. Gradually whisk in the chicken broth and milk, allowing the mixture to simmer and thicken for about 5 minutes. Stir in the thyme, salt, and pepper.
5. Combine the cooked wild rice, shredded chicken, sautéed vegetables, and creamy sauce in a large bowl. Mix until well combined.
6. Pour the mixture into the prepared baking dish, spreading it evenly. Sprinkle the top with Parmesan cheese.
7. Bake in the preheated oven for 25-30 minutes, or until the casserole is bubbling and the cheese is golden brown. Let it cool slightly before serving.

The aroma of this casserole baking is enough to gather everyone around the table, just as my family would do back in Asheville.