Step 1

Gently lower eggs into a medium saucepan of boiling salted water and cook 6½ minutes. Transfer eggs to a bowl of ice water with a slotted spoon and let cool until just warm. Peel and set aside.

Step 2

Meanwhile, whisk sugar, turmeric, ½ cup vinegar, 1 tsp. salt, and ½ cup water in a medium bowl. Add vegetables and sweet onion and let sit until slightly softened and pickled; ideally you want these to sit at least 1 hour, but if you are short on time, 10 minutes and massaging gently to soften a bit will get the job done.

Step 3

Place feta in a small bowl and drizzle with ¼ cup oil and remaining 2 Tbsp. vinegar. Let sit at least 5 minutes.

Step 4

Drizzle toast with oil and tear into large pieces. Place in a large bowl with lettuce. Drain pickled vegetables and add to bowl. Drizzle marinating liquid from feta over, season with salt, and toss well.

Step 5

Cut eggs into quarters. Divide salad among plates; top with eggs and marinated feta and sprinkle with sumac.

Step 6

Do Ahead: Eggs can be made and vegetables can be pickled 4 days ahead; cover and chill. Feta can be marinated 1 week ahead; cover and chill.