1. Preheat the oven to 375°F (190°C) and lightly grease a 9×13-inch baking dish.

2. Bring a large pot of salted water to a boil and cook the orzo until al dente according to package instructions. Drain and set aside.

3. Blanch the broccoli florets in boiling water for 2 to 3 minutes, then transfer them to ice water to preserve their color and texture. Drain thoroughly.

4. Heat olive oil in a large skillet over medium heat. Cook the chicken until fully cooked and lightly golden. Remove from the skillet and set aside.

5. In the same skillet, melt the butter and sauté the diced onion until softened. Add the garlic and cook for 30 seconds until fragrant.

6. Stir the flour into the onion mixture and cook for 1 minute while stirring continuously.

7. Slowly whisk in the chicken broth, milk, and heavy cream until smooth and slightly thickened.

8. Add Italian seasoning, paprika, garlic powder, onion powder, salt, and black pepper. Stir well.

9. Reduce the heat to low and mix in the cheddar cheese, mozzarella cheese, and Parmesan cheese until fully melted and creamy.

10. Add the cooked orzo, chicken, and broccoli into the sauce and stir until evenly coated.

11. Transfer the mixture into the prepared baking dish and spread evenly.

12. Top with extra cheese if desired and bake uncovered for 20 to 25 minutes until hot and bubbly.

13. Broil for 1 to 2 minutes for a golden cheesy top if preferred.

14. Remove from the oven and let the casserole rest for 5 to 10 minutes before serving. Garnish with fresh parsley and enjoy.