Preheat & Prep: First things first! Get your oven preheating to a high broil setting. Lightly grease a standard 8x8 or 9x9 inch baking dish.

Cook the Macaroni: Cook your macaroni according to the package directions until *al dente*. Some swear by boiling it longer (up to 20 minutes) for a super soft, sauce-absorbing noodle, but we love the classic texture. Drain it well and set it aside.

Make the Roux: In a large saucepan or Dutch oven, melt the butter over medium heat. Sprinkle in the flour and whisk constantly for about 1-2 minutes. You're looking for a smooth, bubbling paste—this is the foundation of your amazing sauce!

Build the Creamy Base: Slowly, and while whisking, pour in the whole milk, heavy cream, and evaporated milk. Keep whisking until the mixture is perfectly smooth. Let it come to a gentle simmer, stirring often, until it thickens enough to coat the back of a spoon.

Create the Silky Cheese Sauce: Now for the magic. Turn the heat down to low—this is crucial! Add the American cheese slices first. Watch as they melt and instantly make the sauce glossy and stable. Once they've vanished, start adding your shredded cheeses in handfuls, stirring until each batch is fully melted before adding the next. This patient process is your ticket to the smoothest sauce imaginable. Season with salt and pepper to taste.

Add Richness (Optional): If you're using the egg yolk for that next-level richness, temper it first. Whisk a spoonful of the hot cheese sauce into the yolk in a separate bowl, then pour that mixture back into the main pot, stirring continuously to incorporate it smoothly.

Combine & Coat: Gently fold your cooked macaroni into the finished cheese sauce. Stir until every single noodle is beautifully and generously coated.

Prepare for Baking: Pour the mac and cheese into your prepared baking dish. Sprinkle a final, light layer of shredded cheese over the top for that perfect crust.

Broil to Golden Perfection: Place the dish under the broiler for 3 to 5 minutes. Keep a close eye on it—it happens fast! Remove it once the top is gloriously golden brown and bubbly. Let it rest for a few minutes before serving hot.