This surprising biscuit does many things that a biscuit shouldn't - but it's been a roaring success among Fortnum's biscuit connoisseurs. Each buttery biscuit is made with fresh ginger and just the right amount of chilli; as you munch, the heat builds up slowly and finishes with a warm and well-judged chilli kick. Infernally tempting, it's the biscuit that bites back.