Common onions are normally available in three colour varieties. Yellow or brown onions (called red in some European countries), are full-flavoured and are the onions of choice for everyday use. Yellow onions turn a rich, dark brown when caramelized and give French onion soup its sweet flavour. The red onion (called purple in some European countries) is a good choice for fresh use when its colour livens up the dish; it is also used in grilling. White onions are the traditional onions used in classic Mexican cuisine; they have a golden colour when cooked and a particularly sweet flavour when sautée