Begin by bringing a large pot of salted water to a boil over high heat. Add the elbow macaroni and cook according to package instructions until al dente, typically around 7–8 minutes. Drain the pasta in a colander and set aside.

In a medium saucepan, melt 4 tablespoons of unsalted butter over medium heat until bubbly. Whisk in ¼ cup of all-purpose flour, cooking for about 1 minute until lightly golden. Gradually pour in 3 cups of milk, stirring constantly for 5–7 minutes until thickened.

Remove from heat and stir in 2 cups of sharp cheddar cheese, 1 cup of mozzarella cheese, and 1 cup of Gruyere cheese until fully melted and creamy.

Add 1 teaspoon of garlic powder, ½ teaspoon of onion powder, and season generously with salt and pepper. Stir until smooth and well combined.

Fold the drained macaroni into the warm cheese sauce until every piece is coated. Transfer the mixture into a greased 9x13-inch baking dish.

Sprinkle 1 cup of breadcrumbs on top, ensuring an even coverage.

Bake in a preheated oven at 350°F (175°C) for 25-30 minutes until golden brown and crispy. Allow to cool for 5 minutes before serving.