White sauce, otherwise known as béchamel, is the basis of a catalogue of other dishes you’re going to want to make: lasagne, fish pie, pasta bake, macaroni cheese. It is easy. It is not something you want to buy in a pot. It is good exercise for the arms (whisk whisk whisk!).
You only really need three ingredients: butter, plain flour and milk.
However, I strongly recommend adding a few more: freshly cracked black pepper, nutmeg, mustard powder.
And then usually one last one, to make it into a cheese sauce.
Let’s start with the first three:
500ml whole milk
First you need to make a roux, which is just a mixture of butter and flour that serves to thicken sauce. Heat the butter in a large saucepan (ideally not non-stick or it might scratch if you need to use a whisk) until it just starts to foam – don’t let it colour or it’ll flavour the sauce. Tip in the flour, and cook it for two minutes over a medium heat to get rid of the floury taste.
Remove from the heat and pour in a tiny splash of milk – about a tablespoon’s worth. With a wooden spoon, stir it into the roux to start to loosen it up. Tip in another tiny bit and repeat – you want to beat it quickly to prevent lumps forming. Slowly add milk until it’s a smooth paste, then return to the heat to keep adding milk, more confidently now but always stirring. When it’s thinned a bit you’ll want to switch to a whisk to ward off lumps. Note: there are recipes where you just tip milk, butter and flour in together and heat, but I’ve never managed to get them lump-free.
Keep the heat at medium and cook the sauce for around 10 minutes, until it’s thick.
Now you add the flavour: 1/4 teaspoon of ground nutmeg, 1/2 a teaspoon of mustard powder or a teaspoon of Dijon mustard, grind in lots of black pepper, a bit of salt – all of these are to your preferences, so taste as you go. And then, if you’re making macaroni cheese or similar, a good handful of grated cheese. This is a great place to use up leftovers, so don’t stick to cheddar: use whatever you have at the back of the fridge or freezer, including blue and goat’s (but go easy on both, a tablespoon will have a big impact) or soft cheeses.
To store it, pour into a jug or container and, while still warm, cover with clingfilm to prevent a skin forming.
White and cheese sauces freeze well, or will last in the fridge for a week.
A classic béchamel sauce requires the milk to be infused with flavourings such as bay, mace, peppercorns, onion, cloves and parsley before you use it. That’s wonderful, but adds 25 minutes onto the time it takes to make it. I really wouldn’t bother if you’re adding cheese, and I don’t usually have time either way, but you might, in which case:
500ml whole milk
1 bay leaf
10 whole peppercorns
Cut the onion in half and push a clove into each half. Put everything into the milk and slowly heat until it’s just about to start simmering, taking about five minutes to do so. Turn off the heat, pour it all into a jug and leave for around 2o minutes for the flavours infuse. Strain it so you’re left with just the milk, and then use that to make your béchamel.