In a medium saucepan, melt the butter over medium heat. Once melted, add the onion and cook until softened, but not browned, about 5 minutes, stirring occasionally. Turn the heat down to low, add the garlic, and cook for 30 seconds, stirring constantly.
Whisk in the flour and cook for 1 to 2 minutes, stirring constantly.
Whisk in the chicken broth and milk. Bring to a simmer (it will thicken), whisking constantly.
Whisk in the cream cheese until smooth, and then whisk in the salt, sweet paprika, and black pepper.
ASSEMBLE THE CASSEROLE:
Preheat the oven to 375℉. Spray the inside of a 9x13-inch casserole dish with nonstick spray.
For the broccoli, fill a medium saucepan ⅔ full with water. Bring to a full rolling boil, salt the water, and add the broccoli. Cook for 3 minutes and then drain the broccoli.
Add the rice, chicken, broccoli, creamy sauce, and 2 cups shredded cheddar to a large bowl and stir to combine.
Transfer the mixture to the prepared casserole dish and sprinkle the remaining 1 cup shredded cheddar on top.
Cover the dish with foil and bake until the casserole is warm throughout and the cheese is melted, about 20 minutes. Remove the foil and broil a couple minutes to brown the cheese on top. Garnish with fresh parsley, and serve.
Notes
If you’re making the rice from scratch, you’ll need about 1 1/2 cups of uncooked rice to yield 3 cups of cooked rice.