In a large mixing bowl, slice one medium red onion into thin rings and add them to the bowl. Chop a handful of fresh parsley and add it with two tablespoons of sumac, a splash of red wine vinegar, and three tablespoons of extra virgin olive oil. Sprinkle in a pinch of kosher salt. Using your hands, gently massage the onions and herbs together for about 2-3 minutes until the onions are slightly softened and evenly coated.

Cover the bowl with plastic wrap and let the mixture marinate at room temperature for 20 minutes.

After marinating, give the mixture another quick toss to redistribute the ingredients. Serve the Sumac Onions alongside grilled meats, as part of a mezze platter, or on sandwiches for a burst of flavor.