Combine all ingredients for the gozleme except olive oil in a large bowl. Mix with a spoon until just combined. Turn onto a flour dusted surface and knead for a few minutes until smooth. If you feel the dough is too tough (it should feel pliable like a squishy tummy or little bean bag toy when poked) use a little extra water and knead some more. Knead until the dough ball is smooth and has no cellulite.
Return to the bowl. Cover with a tea towel and set in a warm corner of your kitchen for about 30 minutes to prove.
At this point the dough would have doubled in size. Knead in the olive oil to get a smooth dough ball. Cover and set aside for another 30 minutes.
Divide dough into 6 balls. Roll each dough ball into a large rectangle. Dust with extra flour as needed to avoid sticking. Roll it as thin as you can without tearing the pastry. When you place your hand under it you should be able to see through the pastry (the pastry should be thin enough to be translucent).
Scatter spinach, feta and chilli flakes (if using) in the centre of the rolled pastry. Fold the ends over like an envelope, brushing with water to seal and pinch the pastry.
Dust the folded gozleme lightly with extra flour and gently roll it out to three times the folded size.
Grease a large frying pan with olive oil and pan fry the gozleme on each side for a couple of minutes until golden.
Cut into triangles (or squares) and serve hot with lemon wedges.
Variations - You can bulk up the filling with cooked and shredded spicy chicken or sliced mushrooms.Storage - Stuffed and rolled gozlemes can be stored in tupperware or glass containers in the fridge (separated by baking paper) for up to 2 days. Remove and pan fry as required. A note on salt - I usually use 1/2 teaspoon sea salt flakes. If you are using regular (finer) salt, obviously use less of it. Gozleme recipes often call for a pinch of salt which is okay but you want your dough to have a perfectly salted flavour if you taste test. You don't want the dough to be bland.