Preheat the oven to 350°F. Spray a 13 x 9-inch baking dish with cooking spray. Set aside.
Cook the macaroni in salted water per the package directions until al dente. Drain well, pour into a mixing bowl and set aside.
Mix the shredded cheese together. Set aside.
In a medium-size heavy bottomed saucepan melt 1/2 cup butter over medium heat.
To the melted butter add the flour, salt, Dijon and black pepper. Mix until the flour has been absorbed by the butter stirring constantly.
Increase the temperature to medium high and gradually whisk in the milk. Whisk constantly to prevent clumping. Bring to a boil then immediately lower the heat to low. Simmer for 3-5 minutes gently bubbling stirring occasionally to prevent sticking.
Turn off the heat. Add the cream cheese to the sauce. Stir until melted.
Remove from the heat, add 3 cups shredded cheese mix. Stir until melted. Pour the sauce over the macaroni. Mix until evenly coated.
Pour 1/2 into the baking dish. Top with 1 cup shredded cheese. Repeat with macaroni then top with the final 1 cup of shredded cheese. Dot the top with 2 Tbsp butter.
Place into the oven and bake for 30-40 minutes or until the top is golden and the edges are bubbly.