Ingredients250g butter (the best you can get. Unsalted of course)150g – 200g shallots20cl white wine10cl white wine vinegar10-20cl cream (very optional)MethodCut the butter into 1cm cubes and put it back into the fridge.Now chop your shallots VERY finely. Very. 1mm dice. It’s easier, as I may have mentioned, when you’re on your 200^th kilo of them.Put the shallots, wine and wine vinegar into a saucepan (sauteuse, if you want to be smart) and bring gently to a boil then allow to simmer. Reduce the liquid down to almost nothing – 5-10 minutes. Don’t do it too quickly, you want the shallots to absorb the flavour of the liquid and vice-versa. You can use the time to argue with any passing French person about the exact proportions of wine and vinegar you should be using, or even if you should be using wine or vinegar at all. This may get quite heated but you probably won’t need a knife, although you should keep one within reach.When the liquid has all almost but not quite gone, reduce the heat by half and start adding in the butter piece by piece, stirring it in with a whisk energetically. Don’t, whatever you do, show your chef the page in the official recipe book which suggests that the butter you use should be softened. Well, not unless you want to drive him into an apopleptic rage, that is.If you’re reet posh you may wish to strain the sauce, but most people prefer this sauce with the bits of onion in it so don’t bother. Unless, as I say, you’re posh.You should serve it straight away, or if you have to keep it at 45C-50C for a sort time. It can’t be made in advance and reheated, it will separate out and you’ll need to start over.Nap it over fish, as is traditional, or if you’re a daring radical think of adding some chopped herbs or vegetable purée (peppers, for example, or dill) and serve it with vegetables.This is my favourite sauce, I should note. Usually I have to make double portions because, as my wife puts it, ‘Je le mange à la louche’, I eat it by the ladleful.