Begin by preheating your oven to 350°F (175°C) to ensure it's ready for baking.
In a large skillet, pour in the olive oil and heat over medium heat. Once hot, add the finely chopped onion and minced garlic. Sauté for about 3 minutes, or until the onion becomes translucent and fragrant.
Next, add the diced carrots and celery to the skillet. Continue to cook for an additional 5 minutes, stirring occasionally, until the vegetables are tender yet crisp.
In a large mixing bowl, combine the cooked rice, shredded chicken, steamed broccoli florets, and the sautéed vegetable mixture. Pour in the chicken broth and cream of mushroom soup. Season with dried thyme, paprika, salt, and pepper. Mix thoroughly until all ingredients are evenly combined.
Carefully transfer the mixture into a greased 9x13 inch baking dish, spreading it out to create an even layer across the bottom.
Generously sprinkle the shredded cheddar cheese over the top of the casserole, allowing it to melt beautifully as it bakes.
Cover the baking dish tightly with aluminum foil to trap moisture, and place it in the preheated oven. Bake for 30 minutes.
After 30 minutes, remove the foil and continue to bake for another 15-20 minutes. Cook until the cheese is bubbly and has turned a lovely golden color.
Once baked, remove the dish from the oven and allow it to cool for about 5 minutes before serving. For an added touch, sprinkle with fresh chopped parsley before plating.
Notes
Using rotisserie chicken makes this recipe quicker and easier.