The American clocked 1 minute, 26.16 seconds down the Olympia delle Tofane course, finishing a massive 0.61 seconds in front of German rival Maria Hoefl-Riesch, with Tina Maze of Slovenia third, 0.86 back.
While she finished second in Saturday's wind-affected downhill, Vonn hadn't won since taking a super-G on home snow in Beaver Creek, Colorado, on Dec. 7. Last weekend in Bad Kleinkircheim, Austria, she struggled with a stomach illness and uncharacteristically missed the podium in two speed races.
This was Vonn's 47th career victory and moved her ahead of retired Austrian great Renate Goetschl with 46. Only Austria's Annemarie Moser-Proell (62) and Switzerland's Vreni Schneider (55) have more.
The last of the top-ranked skiers to start, Vonn led at every interval and was even more than a second ahead of Hoefl-Riesch at the last checkpoint. While she lost nearly half of her lead over Hoefl-Riesch on the lower section of the course, Vonn celebrated as soon as she crossed the finish line, hardly even looking to see her time.
It was Vonn's sixth career win in Cortina, moving her within four of Goetschl's record for victories in a single resort, which was established in Cortina.
Vonn also tied Goetschl for the most super-G wins on the all-time list with 17 each, and extended her lead in both the overall and super-G standings. She holds a 291-point lead over Maze in the overall standings and is 87 points ahead of Switzerland's Fabienne Suter in the super-G ranks.
The race was held in perfect conditions, under clear skies with no wind and the snow grippy like the skiers prefer it. Still, 15 skiers did not finish their runs, including the first racer out of the gate, Margret Altacher of Austria, who lost control and hit the safety netting at full speed but then got up and skied down under her own power.
The women travel next to Kranjska Gora, Slovenia, for slalom and giant slalom races next weekend.