Best Baked Mac and Cheese

Preheat
oven to 350 degrees Fahrenheit.

Over high heat, bring a large pot of salted water to a boil. Cook, stirring occasionally, until the pasta is just a little softer, about 6 minutes.

Drain the pasta and rinse it under cold water, reserving 1 cup of the cooking water.

Meanwhile, cut the bread into 1-inch cubes by removing the crusts. Pulse the bread in a food processor until it is broken up into bean-sized pieces.

In a large skillet over medium heat, melt 3 tablespoons of butter. Cook, stirring constantly, until the breadcrumbs are toasted, about 5 to 10 minutes.

Season with salt and pepper after removing from the fire.

In a large saucepan over medium heat, melt 4 tablespoons of butter. Combine the flour, mustard powder, and cayenne pepper in a mixing bowl

. Cook, whisking continually, for about 2 minutes, or until smooth and slightly browned. Cook, whisking occasionally, for about 7 minutes, or until the sauce begins to boil and thicken, then remove from heat.

Until totally melted, stir in the fontina, Gruyere, and all but 1 1/2 cups of the Cheddar. To make a creamy sauce, stir in the pasta, adding the leftover pasta water as needed. Salt & pepper to taste.

In a small microwave-safe bowl, melt the remaining 1 tablespoon butter. Melt the butter in a 9-by-13-inch glass or ceramic baking dish. In the prepared dish, spread the pasta mixture.

The remaining Cheddar should be equally distributed over the macaroni, followed by the toasted breadcrumbs. Bake for about 25 minutes, or until heated through and slightly bubbling. Allow 10 minutes for resting before serving.