In a large pot, bring salted water to a rolling boil. Add your elbow macaroni and cook according to package instructions, usually around 7-8 minutes. You want them al dente, as they will continue cooking in the sauce.

While your pasta cooks, melt the butter in a separate saucepan over medium heat. Once melted, sprinkle in the flour and whisk continuously for about 1 minute until it forms a paste — the roux.

Slowly pour in the milk, whisking continuously. Cook for about 5 minutes or until the mixture thickens slightly.

Reduce the heat to low and add the mustard powder, garlic powder, salt, and pepper. Stir in the shredded cheese little by little until melted.

Drain the macaroni and carefully fold it into the cheese sauce until well coated.

If you want a crunchy topping, preheat your broiler. Transfer the mac and cheese to an oven-safe dish, sprinkle with breadcrumbs, and broil for 2-3 minutes until golden brown.