Begin by filling a large pot with water and bring it to a rolling boil. Add a generous pinch of salt before adding the elbow macaroni. Cook the pasta until it's al dente, typically 7-8 minutes. Once done, drain the pasta in a colander and set it aside, ensuring it doesn’t stick together.

In a large saucepan, melt 4 tablespoons of unsalted butter over medium heat. Once melted, whisk in ¼ cup of all-purpose flour, stirring constantly for 1-2 minutes until the mixture is light golden and bubbly.

Gradually pour in 3 cups of whole milk while whisking continuously to avoid lumps. Continue to cook, stirring frequently, until the mixture thickens and begins to bubble, about 5-7 minutes.

Remove the saucepan from heat and stir in 2 cups of shredded white cheddar cheese and 1 cup of shredded mozzarella cheese. Add 1 teaspoon of garlic powder, 1 teaspoon of onion powder, and season with salt and black pepper to taste. Mix until the cheese has melted completely for a smooth, creamy sauce.

Toss the cooked macaroni into the cheese sauce, stirring gently to ensure every piece is thoroughly coated.

Preheat your oven to 350°F (175°C). While it’s warming, grease a 9x13-inch baking dish with cooking spray or butter. Pour the mac and cheese mixture into the dish, spreading it evenly.

In a small bowl, combine 1 cup of breadcrumbs with ⅓ cup of grated Parmesan cheese. Sprinkle it generously over the mac and cheese in the baking dish.

Place the baking dish in the preheated oven and bake for 20-25 minutes until the top is golden brown and bubbly.

Once baked, remove the dish from the oven and let it cool for about 5-10 minutes before serving.