Ingredients

• 4 tablespoons unsalted butter

• 4 tablespoons all-purpose flour

• 1 quart whole milk, warmed

• ½ small onion

• 1 bay leaf

• 2 whole cloves

• ½ teaspoon kosher salt, plus more to taste

• pinch of white pepper

• pinch of freshly grated nutmeg

Instructions

Stud the onion with the bay leaf and whole cloves and set aside.

Melt the butter in a heavy-bottomed saucepan over medium-low heat. Add the flour and whisk until smooth. Cook for 2–3 minutes, stirring constantly, to form a white roux. Do not allow the roux to brown.

Gradually whisk in the warm milk, adding it in several additions and whisking until smooth after each addition.

Add the studded onion and bring the sauce to a gentle simmer. Reduce the heat to low and simmer for 20–30 minutes, stirring occasionally and scraping the bottom of the pan to prevent scorching.

Remove the onion, bay leaf, and cloves. Season with kosher salt, white pepper, and a small pinch of freshly grated nutmeg.

Strain through a fine-mesh strainer for a smooth, classic finish. Use immediately or hold warm with a piece of buttered parchment or plastic film directly on the surface to prevent a skin from forming.

Chef's Notes

The finished sauce should be smooth, creamy, and thick enough to lightly coat the back of a spoon.

Common derivatives include Mornay, Soubise, mustard sauce, and cheese sauce.