We make the filling by adding to the spinach the onions, Aleppo peppers and oil along with the feta and combining well. Keep aside.
Place a pastry sheet on a working board and cut in a large circle, about 30 cm. Add in the middle 3 tablespoons of the filling, flattening it but staying within the middle of the sheet. Take the top and bottom end of the round sheet and bring them together, repeating the process for the left and right ends while making sure that they seal well. Repeat the procedure for the other 3 sheets.