White sauce

Melt butter, stir in an equal weight of flour and cook for about 2 minutes without letting it brown. Take the pan off the heat and whisk in cold milk a little at a time; return it to the hob and simmer for 5–8 minutes, whisking, until smooth and thick.

Let it simmer gently for a few more minutes, stirring often, so excess moisture evaporates. If it still needs thickening, whisk a little flour into cold milk until smooth, then add it gradually and cook for at least 2 minutes.

White sauce is the creamy layer in lasagne and a classic base for cauliflower cheese. You can also pour it over fish or vegetables, or stir in grated cheese to make a cheese sauce for pasta.

Cool it promptly, cover the surface or seal it in a container, and refrigerate for up to 2 days. Reheat until steaming hot, whisking as it warms; add a splash of milk if it has thickened.

Yes, but it may separate or turn grainy when thawed. Freeze it in a sealed container, thaw it in the fridge, then reheat gently while whisking firmly; a little milk can help smooth it out.

Yes. Use an unsweetened plant drink in place of milk and a plant-based spread or oil in place of butter; oat or soya drinks work well in savoury sauce. Avoid flavoured or sweetened drinks, which can change the taste.

Béchamel is the classic French white sauce made by thickening milk with a butter-and-flour roux, often flavoured with onion, bay or nutmeg. In everyday cooking, “white sauce” is often used for a similar sauce, though recipes can differ.