CLASSIC MAC & CHEESE

Steps:

• Preheat oven to 375°.
• Butter an 8-inch square baking dish or pan or six 8-ounce ramekins; set aside.
• Fill a 4- to 5-quart pot about 3/4 full of water and add 1 tablespoon of the salt.
• Bring to a boil and add the pasta.
• Cook, stirring once or twice, until tender but firm, about 4 minutes, and drain; reserve the pot.
• While the pasta is cooking, melt 2 tablespoons butter in a medium skillet over medium heat.
• Turn off the heat and add the bread crumbs and Parmigiano-Reggiano; stir until mixed well; set aside.
• Using the same pot you used to cook the pasta, melt the remaining 3 tablespoons butter over medium heat.
• Add the onion and cook, stirring occasionally, until soft and translucent, about 5 minutes.
• Slowly whisk in the flour and stir constantly until the onion is coated with the flour, 30-45 seconds.
• Continue stirring for about 2 minutes more, or until the mixture starts to darken slightly and smell a bit nutty.
• Slowly whisk in the milk, cream, and remaining 1 tsp salt and cook until the mixture is just beginning to thicken and bubble around the edges, 5-7 minutes.
• It should be similar in texture to cake batter.
• If it's soupy, continue cooking until it thickens.
• Add 1 1/2 cups of the cheddar, the Gruyere, mustard powder, cayenne, and nutmeg and stir until the cheeses have melted and the sauce is smooth but not too runny.
• Again, it should be similar in texture to cake batter; continue cooking if too soupy, until it thickens.
• Add the pasta and stir to combine.
• Pour into the prepared baking dish.
• Sprinkle with the remaining 1/2 cup of cheddar and top with the bread crumb mixture.
• Place the dish on a rimmed baking sheet and bake until bubbling and golden brown, about 30 minutes.
• Let cool for 15 minutes before serving.