Step 1

Preheat oven to 350 degrees F.

Step 2

Lightly spray a 9x13 pan with nonstick cooking spray.

Step 3

Add chicken to a medium bowl and season with salt, pepper, garlic powder, onion powder, and paprika. Toss to combine and set aside.

Step 4

Add 2 tablespoons olive oil to a large skillet and heat over medium-high heat until hot. Add the broccoli and sauté for about 30 seconds. Add 1/2 cup chicken broth, cover pan, and lower heat to medium-low. Steam broccoli until tender but not limp, about 2 minutes. Transfer broccoli to the prepared baking pan and distribute evenly.

Step 5

To the same skillet, add 2 tablespoons of butter and melt over medium heat. Add chicken in one layer and sear for one minute without moving chicken then continue to cook and stir chicken until cooked through and golden. Add cooked chicken to the prepared pan on top of the broccoli, distribute evenly.

Step 6

In a measuring cup mix milk, flour and cornstarch until combined.

Step 7

To the same skillet, over medium heat add 2 tablespoons of olive oil. Once hot, add diced onion, stir and cook for 1 minute and add garlic. Sir and cook for another 30 seconds.

Step 8

Add the chicken broth, stir to combine. Add the milk mixture and stir to combine.

Step 9

Add the mustard powder, dried parsley, ground cumin, paprika, and black pepper. Stir to combine. Bring the mixture to a light boil and reduce heat to low. Simmer for about 5-6 minutes, until it thickens.

Step 10

Remove from heat and stir in cubed cream cheese and 1 cup cheddar cheese, until melted, next 1/2 Parmesan cheese until melted.

Step 11

Stir in sour cream until blended. Pour sauce over chicken and broccoli and spread into an even layer.

Step 12

Top with 1 cup cheddar cheese.

Step 13

In a small bowl, combine 1/4 cup melted butter with crushed corn flakes. Sprinkle over the top of the casserole.

Step 14

Cover dish with foil and bake for about 30 minutes.

Step 15

Remove foil and bake an additional 5-10 minutes until topping is golden and crunchy.

Step 16

Serve over mashed potatoes or rice.