Preheat your oven to 375°F. Butter a 9 x 13 baking dish and set it aside.
Cook the pasta in salted water until just under al dente and still firm to the bite. Drain the pasta and run cold water over it to stop the cooking process. Set the pasta aside.
Melt 6 tablespoons of butter in a Dutch oven or stockpot over medium-high heat. Add the chopped onion and cook for 2-3 minutes until the onion begins to soften. Add the garlic and cook for another minute until fragrant.
Add the flour to the pot with the onion and cook while stirring for about 2 minutes to cook out the raw flour taste. Slowly pour in the half and half while stirring the mixture with a wooden spoon so lumps do not form.
Season the sauce with onion powder, garlic powder, nutmeg, cayenne pepper, salt, and cracked black pepper. Continue to cook the sauce for 3 to 5 minutes, or until thickened slightly, while stirring occasionally.
Add two cups of freshly grated smoked gouda cheese and two cups of freshly grated young-aged gouda or white cheddar and stir until the cheese is melted. Add the pasta to the pot and stir until well combined.
Transfer the macaroni and cheese to the prepared baking dish and sprinkle the remaining cup of smoked gouda cheese evenly over the top. In a small bowl, mix the panko breadcrumbs, melted butter, salt, pepper, and chopped parsley together with a fork until combined.
Spread the breadcrumb mixture over the mac and cheese in an even layer and transfer the mac and cheese to the preheated oven. Bake the macaroni and cheese uncovered for 25 to 30 minutes, or until bubbly and golden brown on top. Allow the mac and cheese to cool for about 10 minutes and enjoy!