Place rack in center of oven then preheat to 375 degrees. Coat a 9" x 13" casserole dish with cooking spray then set aside. Bring large pot of water to a full rolling boil over high heat then stir in macaroni and salt. Bring the water back to a boil then reduce heat and cook until the pasta is just beginning to become tender, but still very firm—about 6 minutes. Drain pasta, place it in a large bowl then set aside.
While water is boiling and pasta is cooking, place a large saucepan over medium heat and melt the butter.
Next, add flour then whisk to combine. Reduce heat to low then allow flour and butter to cook for 3 minutes, stirring occasionally.
While the flour and butter cook, heat milk in microwave until warm, but not boiling. Whisk warm milk into the flour mixture until completely dissolved. Add salt, garlic powder, dry mustard, paprika and pepper then whisk to combine. Bring mixture to a boil then reduce heat to medium-low and let simmer for 2 additional minutes.
Stir cheese into the sauce 1 cup at a time, allowing each addition of cheese to melt before adding the next.
Once all of the cheese is incorporated and melted, remove sauce from heat then pour it over the macaroni. Stir to combine then transfer the mixture to the prepared casserole dish.
Sprinkle the top with breadcrumbs then bake 30–35 minutes until sauce is bubbly and slightly brown around the edges. Serve immediately and enjoy!
One Last Thing
Jazz up this recipe by adding green chiles, bacon crumbles, fresh sliced tomatoes or anything else you dream up!