Take a large frying pan, add the olive oil and place on a medium heat. Add the chopped potatoes and cook until they start to crisp, stirring occasionally.
Add the garlic and stir until the aroma is released. Then add the onions and green pepper and cook until softened. Stir in the turmeric and oregano.
Then add the biber salçası, water and balsamic vinegar and stir. Then add the chopped coriander and stir until the water has been absorbed into the mixture. Turn off the heat and leave to cool. Once cooled, add the chopped halloumi and season to taste with salt and pepper.
While your pasty mixture is cooling, take your pre-rolled pastry out of the fridge and leave (as per packet instructions) at room temperature for approximately 45 mins.
Preheat the oven to 200°C (180°C in a fan oven)/ Gas mark 6. Unroll your pastry and using a small side plate or pastry cutter 5 inches in diameter cut 8 discs. You may need to take remaining pastry and roll to make further discs.
Place 1/8th of the filling on one side of one of the circles. Brush the edge of half the circle with beaten egg, then fold over the other half to make a D shape. Crimp the edge using a fork or the back of a knife. Then gently push the tips towards each other to create more of a crescent shape. Make a hole in the top to allow some air to escape and place on a lined baking tray. Repeat with the other 7 circles. Brush with the beaten egg, sprinkle with nigella and sesame seeds and bake on a baking tray for 30 to 40 minutes or until they are golden.
Leave to stand for 10 minutes before eating. Serve with the Borani Esfenaj and other mezze-style dishes.