Chicken Broccoli Macaroni and Cheese

0 Preheat the oven to 350°F.
1 In a large pasta pot, boil the elbow macaroni and frozen broccoli together until the pasta is tender and the broccoli is cooked through. Drain and set aside. (I like to leave mine very al dente so that when the mac 'n cheese bakes in the oven, it doesn't get too soft. Set a timer when you drop the pasta in the boiling water so you don't forget!)
2 Warm the oil in a large Dutch oven over medium heat. When the oil is hot, add the flour, stirring constantly for a few minutes until the mixture has darkened slightly into a blonde roux.
3 Pour the milk into the roux, stirring vigorously as it thickens, then add the mustard. Stir until the components are combined.
4 Temper the egg by taking a few tablespoons of the sauce and whisking them into the egg so the egg doesn't scramble when it hits the heated sauce on the stove. Pour the egg mixture into the sauce once tempered, and stir until combined.
5 Lower the heat, and season the sauce with salt, the Creole seasoning and pepper.
6 Add the shredded cheese to the sauce, and remove from the heat. Stir constantly until the cheese has melted into the sauce.
7 Add the pasta, broccoli and shredded chicken to the sauce mixture. Use a large spoon to stir until the ingredients have all melded together.
8 Transfer the macaroni and cheese to the greased baking dish, and bake for 15-20 minutes, or until bubbly and slightly browned on top.
9 Enjoy warm!