In a large skillet, heat olive oil over medium heat. Add the sliced onions, sugar, salt, and black pepper. Cook for 20-25 minutes, stirring occasionally, until the onions are deeply caramelized.
While the onions are cooking, boil the orzo pasta in salted water according to package instructions, but reduce the cooking time by 2 minutes to keep it slightly firm. Drain and set aside.
Once the onions are caramelized, add the shredded chicken to the skillet and toss to combine. Remove from heat.
In a mixing bowl, whisk together the halal chicken broth, heavy cream, garlic powder, dried thyme, and paprika.
In a greased casserole dish, layer the cooked orzo pasta, followed by the onion and chicken mixture. Pour the broth and cream mixture evenly over the top.
Sprinkle the shredded mozzarella and grated Parmesan cheese evenly over the casserole.
Cover the casserole dish with foil and bake for 20 minutes. Then, remove the foil and bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Remove the casserole from the oven and let it rest for 5 minutes. Garnish with chopped parsley before serving, if desired.
Notes
You can substitute rotisserie chicken for the shredded chicken to save time. For a vegetarian version, replace the chicken with sautéed mushrooms and use vegetable broth.