Step 1

Preheat the oven to 375° and have ready a greased casserole dish.

Step 2

Add the butter to a sauté pan over medium heat. Do not allow the butter to brown. As soon as the butter has melted, add the diced onions and sauté 5-7 minutes, stirring often, until softened.

Step 3

Sprinkle the flour over the onions and stir until combined, about 1 minute. Add the chicken broth one big splash at a time, stirring well after each addition. Add in the half and half, salt, and pepper and stir. Allow the mixture to come to a simmer. Simmer for 3-5 minutes, stirring often, until thickened. Remove from the heat.

Step 4

Add cheese and mayonnaise (if using) in a small mixing bowl, and stir to combine. Set aside until ready to use.

Step 5

In a large bowl, combine the white rice, broccoli, chicken, and sauce. Stir to combine, and transfer the mixture to the prepared baking dish. Scatter the cheese across the top, followed by the Corn Flakes.

Step 6

Cover the dish with aluminum foil and bake for 20 minutes. Uncover the dish and continue baking for 10 minutes more. Allow to cool slightly, serve, and enjoy.