This recipe is so simple, and yet is the tastiest butternut soup ever! I am quite sure that the chilli pepper has a great deal to do with its success, it really is just a hint of a burn, but brings out the rich, nutty flavour of the squash perfectly. For this recipe to be truly wonderful, a home-made chicken stock is the ideal choice, so the little time it takes to boil up some chicken carcasses and herbs is well worth the trouble, there are loads of simple recipes for chicken and other stocks in almost every cookbook and on most cooking websites. If you don't want to take the time to make your own stock though, then make one from a stock cube or powder. I do not honestly know what can be used as a substitute for the butternut squash, if it is not available in your country, because pumpkin does not work well, although it does look similar to a butternut in colour. The texture of a butternut is much smoother and finer than pumpkin, and it is a lot sweeter. Perhaps it is rather more like a sweet potato in both texture and colour than a pumpkin.