Preheat the oven to 350°F (175°C).
Cook the elbow macaroni according to package instructions until al dente. Drain and set aside.
In a saucepan, melt the butter over medium heat. Stir in the flour and cook for about 1 minute until smooth and bubbly.
Gradually whisk in the milk, stirring constantly until the mixture thickens and comes to a gentle boil.
Remove from heat and stir in the cheddar, mozzarella, gouda, blue cheese, garlic powder, salt, and pepper until melted and smooth.
Combine the cooked macaroni with the cheese sauce, mixing thoroughly to ensure the pasta is well-coated.
Transfer the macaroni and cheese mixture into a greased baking dish. Sprinkle bread crumbs on top, if desired.
Bake in the preheated oven for 25-30 minutes or until the top is golden and bubbly.
Remove from the oven and let cool for a few minutes before serving.