Velouté Sauce | Classic French White-Stock Sauce

Melt the butter in a heavy-bottomed pot over medium-low heat. Once the foaming subsides, add the flour. Cook, stirring constantly: the mixture will first clump, then turn into a smooth paste as the raw-flour smell fades and a light biscuit aroma develops. Keep the color pale yellow; a browned roux loses thickening power and darkens the sauce.

Warm the chicken stock in a separate container. Add one ladleful to the roux and whisk quickly until smooth. Once the paste becomes a smooth cream, add the remaining stock in three additions, mixing thoroughly each time. Adding all the cold liquid at once creates lumps; warm liquid and gradual additions prevent them.

Cook the sauce just below a boil, stirring occasionally. Skim off the foam and fat that collect on the surface; this step determines how clear the sauce will be. It is ready when it coats the back of a spoon and a line drawn through it with your finger stays open. Remove from the heat and add the lemon juice, salt, and black pepper. Strain through a fine-mesh strainer if desired.