Thoroughly wash and scrub 2 pounds of waxy potatoes under cool, running, drinkable water.
In a large pot of cold water, add potatoes and ½ cup of kosher salt. Over high heat, bring to a boil and cook potatoes until fork tender, about 15 minutes. Drain and let cool slightly.
Add potatoes to a rimmed baking sheet. Use the bottom of a large measuring cup or glass to smash the potatoes individually.
Drizzle them with ⅓ cup of extra-virgin olive oil and season with ½ teaspoon of kosher salt and ¼ teaspoon of freshly ground black pepper. Roast until golden brown and crispy, about 30-35 minutes.
In a small bowl, add 1 cup of pasteurized plain whole milk Greek yogurt, 4 cloves of grated garlic, and 1 tablespoon of water to thin it out.Season with kosher salt and freshly ground black pepper to taste. Stir to combine and set aside.
Spread yogurt on the bottom of a large serving plate and top with baked smashed potatoes. Add ¼ cup of crumbled pasteurized feta cheese, 1 teaspoon of sumac, and a drizzle of extra-virgin olive oil.
Thoroughly wash a small handful of chives, a small handful of fresh dill, and a small handful of fresh flat-leaf parsley under cool, running, drinkable water.
Chop all the fresh herbs and scatter over the potatoes. Garnish with flake salt and freshly ground black pepper. Eat up, Mama!