01 -
Preheat the oven to 350°F. Grease a 9 x 13 inch (3 quart) baking dish with cooking spray or melted butter and set aside.
02 -
In a small bowl, stir together the panko breadcrumbs, melted butter, and seasoned salt. Set the topping mixture aside.
03 -
Bring a large pot of salted water to a boil. Add macaroni and cook until nearly al dente, about 2 minutes less than package instructions. Drain, transfer pasta to a large bowl, and toss with a small amount of olive oil or butter to prevent sticking.
04 -
In a large saucepan over medium-high heat, melt the butter. Add flour and whisk to form a roux, continuing to stir for about 1 minute to cook out the raw flour taste.
05 -
Gradually pour in the whole milk, whisking constantly, followed by half and half. Cook, continuing to whisk, until the mixture is smooth and begins to thicken, about 6 to 8 minutes.
06 -
Whisk in black pepper, nutmeg, garlic powder, and dry mustard. Allow the sauce to reach a gentle simmer until it thickly coats the back of a spoon.
07 -
Reduce heat to low. Add sharp cheddar in portions, stirring after each addition until completely melted. Repeat with white cheddar and then Gruyère cheese, stirring until the sauce is smooth and creamy. Remove from heat.
08 -
Pour the cheese sauce over the cooked pasta and mix until evenly coated. Adjust seasoning with additional salt and pepper if needed.
09 -
Transfer the cheesy pasta mixture to the greased baking dish, smoothing the top into an even layer. Sprinkle the prepared panko topping over the pasta.
10 -
Bake in the preheated oven for 20 minutes, or until the topping is golden and the cheese is bubbling. For an extra golden crust, broil for 2-3 minutes, monitoring closely to avoid burning.
11 -
Remove from the oven and allow the baked mac and cheese to rest for 10 minutes before serving.