Rangers' mercurial captain won a first-half penalty with a superb piece of skill and then nonchalantly dinked the spot-kick past Royals keeper Adam Federici and into the net.
The west Londoners were reduced to 10 when Bradley Orr saw red on the stroke of half-time.
But Taarabt's vision helped set up a second for Alejandro Faurlin and, after Shane Long had pulled one back, the Moroccan's free-kick was turned in by Tommy Smith as Rangers ended a run of four successive draws.
With Cardiff not in action until Sunday against Swansea, Neil Warnock's side lifted themselves back to the summit after extending their club-record unbeaten start to 15 games.
Source: PA