Select spinach, peel and chop onions, sauté with 2 tablespoons oil in saucepan over low heat, stirring occasionally, for 4-5 minutes until golden.
Cut spinach 1 cm thick, add to onions, stir through and steam covered for about 10 minutes until soft.
Remove from the heat, season well with salt and freshly ground pepper, let cool until lukewarm and stir through with half of the eggs.
Coat a 30 x 15 cm baking tray with a little oil, melt butter, mix with remaining oil, milk and remaining egg.
Cut strudel dough (yufka) in half, place on top of each other on the tray, spread liquid between each sheet.
Spread filling evenly over it, place remaining sheets on top in the same way, brush with the rest of the milk mixture. Bake in preheated oven at medium heat for about 30 minutes.
Remove from heat, sprinkle the hot pie with a little water and let it rest for 20 minutes with the lid closed.
This pie is eaten at lunch and dinner with hosaf and cacik. In some regions it is prepared with the addition of minced meat or sheep cheese. Yufka can be spread with milk and yogurt mixed instead of milk and egg.