McGinn produced the goods with an outstanding second-half showing against rock-bottom Dundee, who remain nine points adrift at the foot of the table in their fight to avoid relegation.
McGinn broke the deadlock a minute after the restart and put the rampant Reds further ahead in the 68th minute with a free header.
Dundee substitute Mark Stewart hit a consolation strike with eight minutes left but McGinn dashed any hopes of a comeback and completed his treble in the 88th minute.
But it was Dundee who came out with all guns blazing with the first real chance falling their way inside 60 seconds.
Matt Lockwood's cross wasn't properly cleared by the Dons defence and Kevin McBride latched onto the loose ball only to see his left-foot snap-shot from 12-yards just clear Jamie Langfield's far post.
It was the kind of start which gave them hope but they had to be on their toes at the other end.
Jonny Hayes found some space wide on the right to whip over one of his trademark crosses in search of striker Scott Vernon.
But just as Vernon was about to launch himself at it inside the penalty area, Dundee defender Kyle Benedictus reacted quickest to nod away the danger at the expense of a corner.
Then, midway through the first-half, Aberdeen's Joseph Shaughnessy crossed for Vernon but this time he fired over the bar from 10 yards.
Aberdeen got the second half off to a whirlwind start by taking the lead in the 46th minute. McGinn slid in to break the deadlock with a close-range tap-in from Cameron Smith's cross which eluded the Dundee defence.
The visitors now had a spring in their step as Hayes broke clear down the right shortly after and his pin-point cross was turned just wide by Vernon.
But on-form McGinn made it 2-0 after 68 minutes.
Again Hayes caused havoc with a whipped cross for McGinn, who was all alone to nod past the helpless Douglas and seal the three points.
Stewart pulled a goal back in the 82nd minute with a low drive, but McGinn made the game safe when he knocked home the rebound after Douglas had parried Hayes' shot.