Bechamel Sauce for Lasagna Bolognese
Cook the Cook the roux long enough to avoid a floury taste, but don't let it brown. Whisking constantly while adding flour, then milk, prevents lumps from forming. This sauce is best used fresh, but it can be made 1 day ahead and stored in an airtight container in the refrigerator. Reheat gently in a heatproof bowl over a pan of simmering water before using.