Step 1: Preheat Oven and Prepare Baking Dish: Preheat oven to 375F (190C). Lightly grease a 9x13 inch baking dish.
Step 2: Saut Onion and Garlic: Heat olive oil in a large skillet over medium heat. Add chopped onion and cook until softened, about 5 minutes. Add minced garlic and cook for another minute until fragrant.
Step 3: Cook Chicken: Add chicken pieces to the skillet and cook until browned on all sides and cooked through. Ensure the internal temperature reaches 165F (74C).
Step 4: Prepare Sauce: In a large bowl, whisk together condensed cream of mushroom soup, chicken broth, milk, dried thyme, salt, and pepper.
Step 5: Combine Ingredients: Add cooked rice, frozen mixed vegetables, and cooked chicken to the bowl with the sauce. Stir until everything is well combined.
Step 6: Transfer to Baking Dish: Pour the mixture into the prepared baking dish, spreading it evenly.
Step 7: Add Cheese (Optional): If desired, sprinkle shredded cheddar cheese evenly over the top of the casserole.
Step 8: Bake: Bake in the preheated oven for 30-40 minutes, or until the casserole is heated through and the cheese (if used) is melted and bubbly.
Step 9: Cool and Serve: Let the casserole cool for a few minutes before serving. Enjoy!
Optional Tips and Substitutions:
- For a gluten-free version, ensure the cream of mushroom soup is gluten-free or substitute with a homemade cream sauce made with gluten-free flour.
- Substitute brown rice for white rice for a healthier option.
- Add other vegetables such as broccoli florets, chopped bell peppers, or sliced mushrooms.
- Use different types of cheese, such as Monterey Jack, Gruyere, or Parmesan, for varied flavor profiles.