Instructions

• Preheat your oven: Set a rack in the center of the oven and preheat to 375°F. Grease a 13" x 9" baking dish with butter to prevent sticking later.
• Cook the macaroni: In a large pot of boiling salted water, cook the elbow macaroni, stirring occasionally, until al dente, about 5 to 6 minutes. Once done, drain well.
• Prepare the cheese sauce: In a large saucepan over medium heat, melt 1 stick of butter. Sprinkle flour over the melted butter and cook, stirring, until slightly golden and toasty smelling, around 2 to 3 minutes.
• Whisk in the milk: Pour in 5 cups of whole milk, whisking until well combined. Add 1 teaspoon of mustard powder, along with salt and freshly ground black pepper to taste. Bring to a simmer over medium-high heat, stirring until the sauce begins to thicken, about 2 minutes.
• Melt the cheeses: Remove the pan from heat and add the shredded cheddar, Gruyère, and 1 cup of Parmesan. Whisk until everything is melted and smooth, then stir in the cooked macaroni. Pour the mixture into your prepared baking dish.
• Prepare the topping: In a small bowl, combine 1 cup of panko breadcrumbs, 3 tablespoons of extra-virgin olive oil, and the remaining 1/2 cup of Parmesan. Mix well and sprinkle it evenly over the macaroni. Add more freshly ground black pepper on top for extra flavor.
• Bake: Place the dish in the oven, baking until the mac and cheese is bubbly and golden, about 25 to 30 minutes. Allow to cool for 10 minutes before serving.