Mix 1¼ cups of warm water, 2 teaspoons of sugar, and 2¼ teaspoons of instant yeast. Add 3 cups of all-purpose flour and 2 teaspoons of salt, then knead in ¼ cup of olive oil until smooth.
Put the dough in a greased bowl, cover, and leave to rise for about 1½ hours, until doubled. Divide into 30 pieces, roll them into balls, and leave to rest for 30 minutes.
Meanwhile, preheat the oven to 425°F / 220°C and line two baking sheets with parchment paper.
For the filling, squeeze 450g of thawed frozen spinach very dry. Mix with ¼ cup of chopped parsley, 1 medium diced onion, 2 tablespoons of olive oil, 2 tablespoons of lemon juice, 1 tablespoon of sumac, and 1 teaspoon of salt.
Flatten each ball into a circle. Divide the filling among them, about 2 tablespoons each, and pinch the edges together into triangles. Place on the baking sheets.
Bake for 15-20 minutes, until golden brown on top.
