Choose firm onions that feel heavy for their size.  Avoid those with green sprouts or soft spots.  Keep in a cool, dark and well-ventilated place for up to two weeks.  Once cut, onions may be kept in a tiighly sealed glass jar in the refrigerator for 2 to 3 days.

Slice off root and stem emds.  Remove papery skin and outer layer.  Cut to desired size.  Browning an onion slowly over low heat (called caramelizing) brings out a sweet, mild flavor; over medium heat, a stronger tast emerges.  If cooked quickly in very hot oil, a more jagged flavor develops. All methods are called "browning an onion", buteach produces a big difference in the taste of the dish.