Lamb & Walnut Gul Börek

Preheat oven to 400 degrees F. Coat a large rimmed baking sheet with cooking spray.

Heat 1 tablespoon oil in a large skillet over medium heat. Add onions and cook, stirring often, until soft and translucent, about 5 minutes. Add lamb and cook, stirring occasionally and breaking up any large chunks, until it is no longer pink, 6 to 8 minutes. Drain the mixture in a colander and transfer to a large bowl. Stir in walnuts, parsley, sun-dried tomatoes, za'atar (or oregano), garlic, lemon zest, cumin, salt and pepper. Let cool, stirring occasionally, for 10 minutes.

Whisk vinegar and the remaining 4 tablespoons oil in a small bowl. Place a sheet of phyllo on a clean, dry work surface with a long edge toward you (see Tips). Brush the phyllo with some of the vinegar mixture; lay another sheet of phyllo on top of it. Place 1/2 cup of the lamb mixture along the bottom third of the long edge closest to you, leaving a 1-inch border on the bottom and sides. Roll the phyllo away from you as if you were rolling up a carpet, being careful not to roll too tightly. Brush the roll with some of the vinegar mixture. Starting with one end, roll into a coil and place on the prepared baking sheet. Tuck the loose end underneath. Repeat with the remaining ingredients to make 8 boreks. Brush the tops with the remaining vinegar mixture and sprinkle with sesame (or nigella) seeds.

Bake until golden brown, 25 to 30 minutes. Let cool for 10 minutes before serving.