Preheat oven to 325°F and grease a 9×13" baking dish.

Boil pasta for 1 minute less than package suggests. Drain and drizzle with oil.

Mix shredded cheeses. Divide into three piles: 3 cups (sauce), 1½ cups (middle), 1½ cups (top).

In saucepan, melt butter. Whisk in flour to form a roux. Cook 1 min.

Slowly whisk in milk and half and half. Cook until thickened.

Off heat, stir in seasonings and 3 cups cheese until melted.

Mix sauce with pasta. Layer half in baking dish, then 1½ cups cheese, then remaining pasta. Top with last 1½ cups cheese.

Bake uncovered for 15–20 min. Broil 2–3 min for a crisp top.

Let rest 5 minutes before serving.