The American teenager, who celebrated her maiden World Cup victory last month in Are, dominated both runs to win in two minutes and 1.73, leaving all her rivals far behind.
Sweden's Frida Hansdotter was second, like in Are, a considerable 1.19 seconds adrift while Canada's Erin Mielzynski, her country's own slalom prodigy, finished third some 1.76 off the pace.
World Cup leader Tina Maze, who had made it on the podium of the last nine technical events she entered, failed to complete the course for the first time this season when she straddled a gate halfway down the second run.
Surprised by her immaculate performance after recovering from 'flu, Shiffrin paid homage to last year's winner Marlies Schild of Austria, currently out of action through injury.
"In the second run, I actually thought about Marlies, the way she skied the second leg last year. I shared that energy with her," said the American, who received a coat, a crystal crown and a 60,000 euros ($78,300) cheque awarded to the winner.
Her only moment of doubt in a flawless display of class was when she found herself unable to open the bottle of champagne which was also part of the ceremony. ($1 = 0.7666 euros) (Reporting by Manuele Lang; Editing by Mark Meadows; email@example.com; +44 20 7542 7933; Reuters Messaging:; firstname.lastname@example.org)