Follow these steps to create your own French Onion Chicken Orzo Casserole:

1. Preheat the Oven: Set your oven to 375°F (190°C) to prepare for baking.
2. Cook the Orzo: Bring a large pot of salted water to a boil. Add the orzo and cook until al dente, about 8-10 minutes. Drain and set aside.
3. Sauté the Onions: In a large skillet, heat the olive oil over medium heat. Add the sliced onions and cook, stirring occasionally, until caramelized, about 15-20 minutes.
4. Cook the Chicken: Add the diced chicken to the skillet with the onions, and season with garlic powder, thyme, salt, and pepper. Cook until the chicken is browned and no longer pink, about 5-7 minutes.
5. Combine Ingredients: In a large mixing bowl, combine the cooked orzo, chicken and onion mixture, chicken broth, Worcestershire sauce, and sour cream. Mix well until all ingredients are uniformly distributed.
6. Add Cheese: Fold in half of the shredded Gruyère cheese, reserving the other half for topping.
7. Transfer to a Casserole Dish: Pour the mixture into a greased 9×13 inch casserole dish, spreading it evenly.
8. Top with Cheese: Sprinkle the reserved Gruyère cheese evenly over the top of the casserole.
9. Bake: Place the dish in the preheated oven and bake for 30-35 minutes, or until the cheese is bubbling and golden brown.
10. Rest Before Serving: Once baked, allow the casserole to cool for 5-10 minutes. This resting time helps the casserole set, making it easier to serve.
11. Garnish and Serve: Sprinkle fresh parsley over the top for an added touch of flavor and color before serving.

These simple yet effective steps will guide you in creating your French Onion Chicken Orzo Casserole with ease and satisfaction.