Wash the Yukon Gold or Red Potatoes under cold water and scrub thoroughly. Place them in a large pot, cover with fresh water, and add a pinch of salt. Bring to a boil, then reduce to a simmer for 15–20 minutes until fork-tender.

While potatoes are cooking, whisk together the olive oil, lemon juice, sumac, salt, and pepper in a small bowl until well combined.

Once cooked, drain the potatoes and let them cool slightly. Cut into bite-sized cubes.

In a large mixing bowl, combine the cubed potatoes with chopped parsley, red onion, cucumber, tomatoes, black olives, and feta cheese. Stir carefully to mix.

Pour the dressing over the mixture and gently toss to coat evenly. Adjust seasoning with salt, pepper, or sumac.

Serve immediately or cover and chill for at least one hour to allow flavors to meld. Garnish with extra parsley before serving.