True Scottish Shortbread

"When I was a young kid one or other of us in turn occasionally used to be allowed to wreak havoc in the kitchen. I used to make the most mess - but the best cakes! This is a recipe I asked for from the elderly Scottish pastry cook who used to live opposite. She even had me bake it one time in HER kitchen - none of my siblings were so privileged - boy was I was smug about that! She used to bring over some of the most amazing goodies! I have searched and baked and bought, but never found a shortbread recipe that was anything like as good as this. Fortunately my mum found a 'new' copy of her much-spattered cookbook and she gave me her old one which had this recipe manually type-written and stuck into it. Nobody, but nobody!, bakes better shortbread than I occasionally treat myself to (I DO share some of it!) when I bake using this recipe!!! Do try this one - it's just the ultimate! :) Despite the Scots preference for slightly warmed shortbread I strongly urge you to wait until it's fully cold before devouring - not refrigerated cold, but ideally no warmer (or cooler really) than a cool room temperature. The instructions call for some care in the preparation but as I'm passing on the tips as they were given to me when I was between 8 to 10 years old, I'll pass them on to you rather than leave them out. - She felt they were important for best results, and the resulting shortbread proves she knew what she was talking about! The recipe is very simple and robust enough that a child can make it well, but the best results will come from taking extra special care. This recipe doesn't double well either, sadly. Do especially keep that mixture cool and do it by hand not machine – it’s only a few minutes of fussing about after all! Sorry to those without a set of kitchen scales, recipes in Europe are almost entirely written by weight...."