Preheat oven to 400°F. Put a cooling rack over a rimmed baking sheet.
Place the potatoes on a cutting board, the flattest side down. Using a sharp knife, cut slices about 2 millimeters thick, being careful to only cut about ¾ of the way through the potato.
Combine the olive oil with the spices and kosher salt in a small bowl. Brush the oil mixture all over the potatoes makes sure to brush the cut slices on both sides. Place on the rack and cook for 50–60 minutes or until the potatoes are tender and browned.
Sprinkle with flaky salt and cilantro before serving.