Onions are eaten and grown in more countries than any other vegetable but rarely seem to receive much acclaim. It's time to stop taking the tangy, tear-inducing bulb for granted and give it a round of applause, writes the BBC's Marek Pruszewicz. Deep in the archives of Yale University's Babylonian Collection lie three small clay tablets with a particular claim to fame - they are the oldest known cookery books. Covered in minute cuneiform writing, they did not give-up their secrets until 1985, nearly 4,000 years after they were written. The French Assyriologist and gourmet cook Jean Bottero - a...