Sauté the onion in a frying pan with the extra virgin olive oil. Add the spinach, season with salt and pepper to taste, and cook for about 3 minutes. Turn off the heat and set aside to cool.

Put the flour and salt in a bowl, then slowly add the water while kneading.

Knead the dough for about 10 minutes, or until it becomes smooth.

Shape the dough into a ball, cover it with a damp paper towel, and let it rest for 15 minutes.

Cut the dough into 4 pieces and roll each piece out into a very thin sheet.

Spread the cooked spinach in the centre of the rolled dough, then top with the feta and mozzarella.

Fold the opposite sides over the filling first, then fold the remaining two sides to fully enclose the filling.

Heat a non-stick pan (lightly brushed with oil) over medium heat. Cook one side of the Gozleme until brown spots appear, then turn it over and cook the second side.

Slice and serve warm.