01 -
Halve and peel the onions, then slice them into very thin half moons. If the onions are very sharp, soak the slices in cold water for 10 minutes, drain, and pat dry.
02 -
Place the onions in a nonreactive bowl. Add sumac, salt, and Aleppo pepper if using. Massage gently with your fingertips for 30-45 seconds until glossy and lightly softened.
03 -
Add lemon juice, olive oil, and parsley. Toss until the onions are evenly coated and the parsley is scattered throughout.
04 -
Taste and adjust with more salt, lemon, or sumac. Serve immediately for a crisp bite, or let stand 10-15 minutes for a softer texture.