How to Make It
Preheat the oven to 350°. In a large pot of boiling, salted water, cook the macaroni for 3 minutes (it will still be very chewy). Drain the macaroni and return it to the pot. Drizzle lightly with olive oil and toss well.
Butter a 10-by-15-inch baking dish. In a large bowl, whisk the heavy cream with the half-and-half, milk, eggs, nutmeg, salt and pepper. Stir in the cheddar and Monterey Jack cheeses and the macaroni. Spread the mac and cheese in the prepared baking dish and scatter the cream cheese cubes on top.
Bake the macaroni for 5 minutes. Using the back of a large spoon, spread the melted cream cheese cubes evenly over the surface. Bake for 40 minutes, until bubbling.
Remove the baking dish from the oven and preheat the broiler. Broil the mac and cheese about 3 inches from the heat source until richly browned, about 2 minutes. Let stand for at least 10 and up to 20 minutes before serving.