Macaroni Au Gratin

Ingredients

• 1 1/2 tablespoons kosher salt
• 6 ounces dry elbow macaroni
• 1 teaspoon mild olive or vegetable oil
• 2 ounces grana padano or Parmigiano Reggiano, grated
• 2 ounces Jarlsberg, shredded
• 6 ounces white Cheddar, shredded
• 2 cups heavy cream
• 1/2 to 1 teaspoon sea salt, optional

Directions

1. In a pot, stir together 2 quarts (1.8 liters) water and the kosher salt, then bring it to a boil. Add the macaroni and bring the water back up to a boil. Cook until the pasta is just shy of fully tender, about 5 minutes after the water boils again. Drain in a colander and shake off the excess water. Spread the macaroni on a rimmed baking sheet, drizzle it with the oil, and toss gently so the pieces are lightly coated and do not cling together. Cool completely. You should end up with about 3 cups.
2. Arrange an oven rack about 4 inches (10 cm) below the broiler, then preheat the broiler.
3. In a large bowl, toss the grana padano, Jarlsberg, and white Cheddar until evenly mixed. Divide the cheese into two portions, making one a bit bigger than the other. The smaller portion should be 40% of the cheese mixture, and the larger portion should be 60%.
4. Set a large, deep saucepan over medium-high heat and bring the cream and sea salt, if using, to a boil. Simmer for about 2 minutes. The cream will rise up in a foam, then settle down into a steady simmer. Stir in the macaroni and cook for about 90 seconds, stirring now and then, until the cream begins to lightly thicken and cling to the pasta.
5. Add the 40% portion of cheese a little at a time, stirring after each addition and letting it melt smoothly into the sauce before adding more. Pour everything into a 2 1/2-quart (2.4 liter) ovenproof skillet or baking dish. It will look a little loose, and that is fine. Pile the remaining cheese over the macaroni, set the dish on a rimmed baking sheet to catch drips, and place it under the broiler. Broil, turning the skillet or dish frequently, until the cheese is melted and browned into a golden crust, 3 to 5 minutes. Watch closely, because broilers are all different and the topping can darken fast.
6. Take the macaroni au gratin out of the oven and rest it for 5 minutes. Serve right away.