To make the lamb filling, in a mixing bowl, combine the lamb, cumin, spearmint, oregano, Maras pepper, black pepper, red pepper paste, egg white, and green onion until everything is smooth and creamy. Set aside.
Lightly flour a work surface. Lightly flour a baking sheet.
Place one of the dough balls on the prepared work surface and roll out until 6 to 7 inches in diameter. Divide the lamb mixture into twelve portions, each weighing approximately 11⁄4 ounces. Place one of the lamb portions on the flatbread, flattening it out and spreading it on the dough gently without breaking or tearing the dough.
Make a hole in the center of each yufka and roll the dough from the inside to the outside, moving around the circle so that you have a perfectly even round ring when you are finished. Cut the ring in the middle and coil it up like a serpentine. Tuck the tail into the center and place on the prepared baking sheet. Repeat the process with the remaining dough. (You can freeze the katmer at this point.)
Roll out each serpentine to 5 inches in diameter and 1⁄4 inch thick, being careful not to roll so hard that the filling pushes out of the dough. Some may start to show through the dough, which is okay.
Lightly oil each side of the katmer by brushing with a little olive oil. Place a large cast-iron skillet over low heat. When it is hot, place two katmer (if you can fit them) in the skillet and cook until golden and crisp, about 4 minutes per side. When they are done, you will be able to see some of the juices from the lamb start to bubble out of the dough. Sprinkle lightly with salt and stack them on top of each other. Cover with foil to keep warm. Cut into wedges and serve with a generous amount of the pistachio yogurt.