Preheat the oven to 350°F (175°C).
In a large pot, bring salted water to a boil. Add the elbow macaroni and cook according to package directions until al dente. Drain and set aside.
In a saucepan over medium heat, melt the butter. Once melted, whisk in the flour and cook for about 1 minute until bubbly.
Gradually pour in the milk, whisking continuously to avoid lumps. Add the mustard powder, garlic powder, onion powder, cayenne pepper, salt, and pepper.
Cook the mixture, stirring constantly, until it thickens, about 5-7 minutes.
Remove from heat and stir in the cheddar and mozzarella cheese until melted and smooth.
Combine the cooked macaroni with the cheese sauce, stirring to coat evenly.
Transfer the mixture to a greased 9x13-inch baking dish. Top with breadcrumbs for a crunchy finish.
Bake in the preheated oven for 20 minutes until bubbly and golden on top.
Allow to cool for a few minutes before serving.