Step 1: Prepare the Roasted Garlic

1. Preheat your oven to 400°F (200°C). Slice off the top of the garlic head to expose the cloves. Drizzle with 2 tbsp of olive oil and wrap it in aluminum foil. Roast in the oven for about 30 minutes, or until the cloves are soft and caramelized. Let it cool, then squeeze out the roasted garlic cloves and set them aside.

Step 2: Cook the Rice

2. In a large saucepan, bring 4 cups of chicken broth (or water) to a boil. Add 2 cups of long-grain white rice, 1 tsp salt, and 1/2 tsp black pepper. Reduce the heat, cover, and let it simmer for about 15 minutes or until the rice is tender and the liquid is absorbed. Remove from heat and fluff with a fork.

Step 3: Cook the Chicken and Vegetables

3. In a large skillet, heat 2 tbsp of olive oil over medium-high heat. Add diced chicken pieces and season with 1/2 tsp black pepper, 1 tsp paprika, and 1 tsp dried thyme. Cook until the chicken is browned and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set it aside.
4. In the same skillet, add chopped onions, red and green bell peppers, and minced garlic. Cook for about 5 minutes until the vegetables are soft. Add the frozen peas and carrots, and cook for another 3 minutes. Set the vegetable mixture aside.

Step 4: Prepare the Creamy Garlic Sauce

5. In a medium saucepan, melt 3 tbsp of butter over medium heat. Stir in 3 tbsp of flour, cooking for about 2 minutes to remove the raw flour taste. Gradually whisk in 2 cups of whole milk and 1/2 cup of chicken broth until smooth. Add the roasted garlic, Parmesan cheese, dried Italian seasoning, 1/2 tsp salt, 1/4 tsp black pepper, and a pinch of nutmeg. Simmer for about 5 minutes, or until the sauce thickens.

Step 5: Assemble the Casserole

6. Preheat the oven to 375°F (190°C). In a large mixing bowl, combine the cooked rice, chicken, and sautéed vegetables. Pour in the roasted garlic cream sauce and mix well.
7. Transfer the mixture to a greased 9×13-inch baking dish. Sprinkle with shredded mozzarella and cheddar cheese.
8. Bake for 25-30 minutes, or until the cheese is melted and bubbly. For a golden top, broil for an additional 2-3 minutes.