White Sauce

Pour 2 cups (480ml) whole milk into a small saucepan, set over low heat for 3-4 minutes until it reaches a gentle simmer (around 170°F/77°C, no rolling boil), then remove from heat and set aside. Warming milk prevents lumpy sauce by avoiding temperature shock to the roux.

Place a heavy-bottomed 2-quart saucepan over medium-low heat, add 4 tablespoons (57g) unsalted butter, and melt completely for 1-2 minutes, swirling the pan occasionally, until it foams lightly but does not turn golden or brown.

Add 4 tablespoons (32g) all-purpose flour to the melted butter, whisking constantly to form a smooth, thick paste. Cook for 2 full minutes over medium-low heat, stirring nonstop, to remove raw flour taste; the finished roux will be pale golden and smell lightly toasty, with no dark brown spots.

Add the warmed milk 2 tablespoons at a time at first, whisking vigorously after each addition to fully combine with the roux, until a thick, smooth paste forms. After the first 1/2 cup of milk is incorporated, pour the remaining milk in a slow, steady stream while whisking constantly to prevent lumps from forming.

Increase heat to medium, bring the sauce to a gentle, low simmer (small bubbles breaking steadily across the surface), and cook for 3-4 minutes, whisking occasionally, until the sauce thickens enough to evenly coat the back of a metal spoon; a line drawn through the sauce on the spoon with a finger will hold its shape without running.

Remove the saucepan from heat, stir in 1/2 teaspoon kosher salt, 1/4 teaspoon freshly ground black pepper, and 1/8 teaspoon ground nutmeg. Taste and adjust seasoning if needed; thin with 1-2 tablespoons of extra warm milk if the sauce is too thick for your intended use.