01 -
Combine the onion slices, sumac, and salt in a medium bowl. Gently rub the onion with your hands for about 30 to 60 seconds to blend the salt and sumac well.
02 -
Add the vinegar, oil, and parsley to the bowl. Stir everything together. Cover it up and let it soak for at least 20 minutes before serving, or store it in an airtight container for up to four days.
03 -
Use it as a side salad or as a topping. Toss the onions onto burgers, sandwiches, wraps, or mix them into salads.