Pesto is the pungent, cheesy, garlicky, nutty sauce, with the perfume of freshly picked basil, which is the favourite seasoning for pasta and soups in the region around Genoa in northern Italy. The longest-running contender in the British pesto market is actually a Welsh company, Zest Foods. Managing director Tim Clarke started making and bottling the sauce in his garden shed in 1985 and now he's selling pesto dressings and pesto dips right across the board. It is the heady scent of the herb sweet basil, picked while the sun still shines on it, preserved in the best olive oil, which is the glowing green heart of a Genovese or Provencal pesto. Pesto in itself means no more than 'pounded'. All over Italy (and even in Spain, where the Catalan picada is a pesto) there are mixtures of pounded herbs and nuts. In the south of Italy walnuts take the place of the pine nut of the north, and sometimes flat-leafed parsley replaces basil.