Stir salt into the yogurt until fully dissolved. Taste — it should be noticeably salty. The flavor mellows as the labneh strains and thickens.
Line a fine mesh sieve or colander with two layers of cheesecloth. Pour in the salted yogurt. Bring the corners of the cloth together and tie with kitchen twine. Set the sieve over a tall bowl so the liquid drips freely without the cloth touching the collected whey.
Place the whole setup in the refrigerator. Let it strain for 12 hours for a soft, spreadable labneh — or 24 hours for a firmer texture. For labneh balls, strain for 48 hours. Pour off collected whey if it nears the bottom of the sieve.
Unwrap the labneh and transfer to a bowl or serving dish. Taste and add a small pinch more salt if needed. Stir in a tablespoon of collected whey or olive oil if you want a slightly looser texture.
Spread onto a plate, drizzle generously with olive oil, sprinkle za’atar and flaky salt on top, and add fresh mint if using. Serve with warm pita or flatbread.
