Ingredients4 egg yolks25ml cold water250g butterJuice of half a lemonSaltCayenne pepperMethodHollandaise, as I learned at school, is a sauce émulsionnée instable chaude – an unstable hot emulsified sauce. Which means, basically, whisk it lots and eat it quick.So, cut your butter into small chunks and clarify it in a bain marie if you’re a wuss, directly on the heat if you’re a manly man’s chef. ‘Clarify’, let’s clarify, means separate out the good oily buttery bit from the nasty milk solids. So you heat it gently without stirring, then skim off any scum from the surface and decant the good, clear, yellow stuff off the top and leave the white nasty bits behind.Separate your egg yolks – don’t faff around with half egg shells or squeeze bottles, just crack it and strain it through your fingers, all right?Put the yolks into a shallow saucepan and add the cold water and either on a fairly gentle heat (manly man) or bain marie (wussy wimp) whisk energetically in a figure of 8 with a supple sauce whisk (the kind that’s about 30 cms long top to bottom). Keep doing this until your mixture is, in the words of my textbook, ‘unctuous and mousse-like’.In practice this means for much, much longer than you’d think necessary. The mixture should be at around 60C – enough to make you go ‘Ouch!’ when you test it with a finger – and each stroke of the whisk should leave a VERY clear trail across the bottom of the pan. Add a little warm water – drop by drop – if you think it’s too thick. Take my word for it, you’ll get the hand of this after your first two or three hundred litres of the stuff. How hot? My restaurant chef’s tip was: Hold your hand on the side of the pan whilst whisking; when you smell burning flesh, it’s too hot.Add in the lemon juice and then the WARM butter drop by drop, whisking furiously all the time. You can add the lemon at the end if you prefer, along with a pinch of cayenne pepper.Again, a few drops of warm water will help if you think it’s too thick.And there you go; ready for your Eggs Benedict (beurck) or to be transformed into mustard sauce, mousse line, Maltaise (blood orange) or Mikado (mandarin orange) sauce.Seriously, this isn’t the difficult sauce to make that many fear – put all your ingredients in place and do this last just before serving the appropriate dish (you can keep it if you can maintain a bain marie at 60C but hey…) and you’ll be fine.Then again that’s easy for me to say, 250 practise litres ahead of you….