bechamel
Also known as: béchamel, white sauce
A basic white sauce made by whisking milk into a butter-and-flour roux and simmering until thickened -- one of the foundational French sauces, and a base for countless others once cheese, mustard, or other flavorings are added. Used both as a component in dishes like lasagna and gratins and, in smaller amounts, stirred into a soup or sauce to add body and a creamy richness.
Buying guidance
Not typically sold ready-made -- it's quick enough from scratch (butter, flour, milk) that it's almost always made fresh rather than bought. Pre-made versions exist in some grocery stores as a jarred or refrigerated sauce, but check the ingredient list, since some substitute stabilizers and thickeners for the real butter-flour-milk base.
Substitutions
- Heavy cream, simmered to reduce slightly -- adds richness and body without the flour, though it won't thicken as much on its own.
- A cornstarch slurry stirred into hot milk -- a gluten-free way to get a similar thickened, creamy consistency.
- Plain whole milk or half-and-half -- adds creaminess without the thickening; fine where the bechamel's main job is richness rather than body.
Tips & common mistakes
Adding cold milk to a hot roux, or all at once instead of gradually, is the most common way it turns lumpy -- whisking in warm milk a little at a time, letting each addition smooth out before adding more, keeps it silky. A bechamel that seems too thin usually just needs a few more minutes of gentle simmering rather than more flour, since it continues to thicken as it cooks.
Storage
Keeps refrigerated for a few days in a sealed container; a skin can form on top as it cools, so pressing plastic wrap directly onto the surface before chilling helps prevent that. Reheat gently and whisk well, since it can separate slightly on reheating.