Another tip from the Gore Geeks... it is important to prevent your hands from getting cold in the first place because it takes a long time for them to recover (especially women). Our bodies respond (and sometimes over-react) to temperature changes and moisture , so using layers and then adding insulation is a great solution. At then end of the day, mittens with glove liners seem to be the solution for most,

PS - some mittens have a spot for hand warmers that are easy to activate when needed.