Tom yum, which means ‘sour soup’, is hardly a novel dish. However, the ease with which it can be made, its great flexibility and, of course, that incomparable taste, make it a winner, so we felt the need to include it here. We’ve used an assortment of fresh seafood, but it’s pretty standard to only use prawns – you can also use fish or chicken instead, or even pork (throw in thinly sliced pieces of trimmed fillet and cook for 2–3 minutes). You can adjust the hot, sour, salty and sweet notes to suit yourself but, strictly speaking, this soup should be spicy.