Bring a large pot of salted water to a boil. Add the elbow macaroni and cook according to package instructions until al dente. Drain and set aside.
In a large saucepan, melt the butter over medium heat. Once melted, add the flour and whisk continuously for about 1 minute to create a roux.
Gradually whisk in the whole milk, ensuring there are no lumps. Continue to whisk until the mixture thickens and begins to bubble, about 3-5 minutes.
Lower the heat, then stir in the grated sharp cheddar cheese and Gruyère cheese until fully melted and creamy. Add garlic powder, onion powder, mustard powder, salt, and black pepper, mixing well.
Fold in the cooked macaroni into the cheese sauce until well combined. Drizzle in the truffle oil and mix gently to incorporate the flavor throughout.
Preheat your oven to 350°F (175°C). Transfer the mac and cheese to a greased baking dish.
In a small bowl, combine panko breadcrumbs with a drizzle of truffle oil for extra flavor. Sprinkle the breadcrumb mixture evenly over the mac and cheese.
Place the dish in the preheated oven and bake for about 25-30 minutes, or until the top is golden brown and crispy.
Remove from the oven and let it cool for a few minutes. Garnish with chopped fresh parsley before serving.
Notes
For an extra touch, use fresh truffles if available.