Slice the leeks thinly and place in a bowl
Lightly beat the eggs and add to the leeks together with the rice, half of the oil, 2 teaspoons salt, lots of pepper and the parmesan; mix thoroughly with your hands and leave aside for at least 2 hours to soften the rice; stir often
Heat the oven to 180C/Gas4; pour the remaining oil into a bowl; oil a 24cm spring-form tin and lightly flour it; lay one sheet of filo pastry over the bottom and up the sides of the tin, allowing the ends to overhand the tin; brush with a little oil; lay another sheet of filo pastry over the first and brush with oil again; continue layering the sheet of filo pastry until the tin is completely covered
Spoon the leek and rice mixture into the tin; fold the overhanging pieces of filo pastry over the top to cover the mixture completely; use some more sheets of pastry to cover the top if necessary; make a hole in the top and pour any oil which is left over.
Bake the pie for 45-55 minutes in the preheated oven; cover it with foil if the pastry is browning too quickly; allow the pie to cool in the tin for about 10 minutes before taking out of the tin and placing on a serving platter