Sauté finely diced onion and minced garlic in olive oil over medium heat until softened. Add the lamb mince and cook until browned. Stir in the spices, mixing well before adding the tomato passata, currants, and toasted pine nuts. Simmer for a few minutes until reduced, then allow the mixture to cool.

In a bowl, whisk together the egg, plain yogurt, and melted butter until fully blended. This will help bind the pastry layers and add a delightful sheen.

Carefully open the filo pastry. Lay out four sheets at a time, brushing each layer generously with the yogurt wash.

Scoop a portion of the cooled lamb filling and spread it along one edge of the layered pastry. Roll loosely into a log shape, then coil it into a spiral.

Place the spiral-shaped borek in a greased baking dish. Brush the top with melted butter and sprinkle with sesame seeds if desired. Bake in a preheated oven at 200°C (390°F) for about 40 minutes, or until the pastry is golden brown and crispy.

Allow the borek to cool slightly before slicing into wedges. Pair with a refreshing Lemon Yogurt Sauce for a delightful contrast of flavors.