Preheat the oven to 180°C.
Fry the sliced onions in 15ml of oil for 5 minutes until golden-brown and set aside.
Heat 92ml of oil in a tray until smoking, then coat potatoes in the oil with spices, garlic, and chilli.
Season and roast potatoes for 25 minutes, then remove with a slotted spoon to cool.
Reduce the oven temperature to 160°C.
Combine the cooled onions, potatoes, spinach, and pistachios in a bowl and season well.
Layer three sheets of pastry in a greased 36cm x 24cm dish, brushing each sheet with melted butter.
Spread one third of the vegetable mixture over the pastry.
Add five layers of pastry with butter between them, then add another third of the mixture.
Repeat with five more pastry layers and the remaining mixture, finishing with five buttered pastry sheets and a honey drizzle.
Cut a criss-cross pattern into the top and bake for 40 minutes until crisp and golden-brown.
Serve portions with a spoonful of yoghurt and a sprinkle of sesame seeds.