Lebanese fatayer bil-sbanegh (Small savoury spinach pies)

I really like Lebanese food. Although I'm not very keen on meat, sometimes I eat even meat from the Lebanese restaurant nearby. All the spices and seasoning are just so wonderful.
On the other hand, I really enjoy the vegetarian part of the cuisine. So, after figuring out that 1 Euro is too much to pay for a teeny tiny (minuscule) pie, I decided to make my own. I found the original recipe somewhere on the net, but I 'improved' to suit my taste :)
So, for 20 of these delicious mini pies you will need:

Dough:

250 grams all purpose flour, sifted
160 ml lukewarm water
1/2 teaspoon dry yeast
1 level teaspoon salt
Olive oil for brushing

Filling:

500 grams fresh spinach leaves
1 small ripe tomato, finely diced
1 medium onion, very finely diced
1/2 teaspoon salt
pinch of grated nutmeg
pinch of ground black pepper
juice of half lemon
1 tablespoon sumac* (*see note)

Method:

In a bowl, combine the flour, yeast and salt and gradually add the water. Stir and mix well to make the dough. On a floured surface knead the dough adding more flour if it's sticky. Knead for 5 minutes. Lightly oil a bowl with some olive oil and place the dough. Cover with cling film and let it prove for about 1 and a half to 2 hours.
In meantime, shred the spinach into very thin ribbons, sprinkle with the salt and squeeze as much moisture as you can with your hands. (The spinach has to look dry). Discard the liquid. Put the spinach into a bowl with the diced onion and tomato and add the sumac, pepper, nutmeg and lemon juice. Stir well to combine.
Preheat the oven to 200 degrees Celsius and line baking sheet with baking parchment. Divide the dough in 20 small balls and cover them with tea towel to prevent drying out. Roll each bowl on lightly floured surface with floured rolling pin into circle about 8 centimetres in diameter. Brush the edges with little water and place tablespoon of the filling into the centre of the circle. Fold the dough from 3 sides and pinch the edges to form triangular shapes. Arrange on baking tray and brush lightly with olive oil on all 3 sides. Bake for 25-30 minutes (depending on the oven) or until lightly golden. Take out from the oven and brush again lightly with olive oil. Let them cool and serve at room temperature with some strained yogurt sprinkled with sumac.

* Note: Sumac is Middle Eastern sour spice with peppery hint. If you can't find sumac, you can use zest from half lemon mixed with pinch of salt.
I'm so glad that nearby there's ethnic shop that sells all kind of spices, but my sumac was bought from the Lebanese restaurant nearby :) The chef/owner was happy to sell me the desired amount for very little money :)