- 425ml/15fl oz milk – this can be infused but must be cold
- 20g/¾oz plain flour
- 40g/1½oz butter
- salt and freshly milled black pepper
- When you're ready to make the sauce, put the milk in a saucepan, then simply add the flour and butter and bring everything gradually up to simmering point, whisking continuously with a balloon whisk, until the sauce has thickened and becomes smooth and glossy.
- Then turn the heat down to its lowest possible setting and let the sauce cook very gently forminutes, stirring from time to time. Meanwhile, taste and add seasoning.