In a large, heavy-bottomed skillet, warm the oil over medium heat. Add the onions and salt and caramelize until light brown, 45 to 60 minutes.
Add the brown sugar and vinegar and stir until incorporated. Let cool.
2 Tbsp. vegetable oil
4 to 5 white onions, thinly sliced
2 tsp. kosher salt
²∕³ cup brown sugar
¹∕³ cup apple cider vinegar
4 to 5 white onions, thinly sliced
2 tsp. kosher salt
²∕³ cup brown sugar
¹∕³ cup apple cider vinegar
This article appears in June 2015.