Preheat the oven to 180C fan, 200C regular oven.

Method:

1. You will need a large pie dish or rectangle baking pan. Brush it with melted unsalted butter.
2. To make the filling, toss the grated zucchini with the teaspoon of salt and leave in a colander to drain for at least an hour. Give it a shake and toss from time to time. Then take handfuls of the zucchini and squeeze out as much liquid as you can, or wring it out in a tea towel.
3. Lightly beat the eggs in a large bowl with plenty of pepper. Stir in the feta, mozzarella, rice or burghul and mint. Then add the zucchini and keep the mixture in the fridge until required.
4. To assemble the pie, lay 10 sheets of filo on a tea towel, cover them with a dry tea towel and then with a damp tea towel. Keep the filo covered as you work to prevent it becoming dry.
5. Use a wide pastry brush to melted unsalted butter on the filo sheets and work as quickly as you can.
6. Arrange 5 sheets individually brushed into the baking dish so that the ends hang over the sides.
7. Tip the zucchini mixture into the filo-lined dish and spread out evenly. Fold the overhang in over the filling. Brush the remaining sheets of filo with unsalted butter as before and place over the filling.
8. Brush melted butter on top. Tuck the surplus filo snuggly in around the pie.
9. Score the top couple of sheets of filo with a sharp knife in a diamond pattern or into segments where the pie is to be cut later. Make air vents by plunging the knife right through the top layers a few times. Sprinkle the top with sesame seeds. 
10. Bake the pie on a tray in the middle of the oven for one hour or until crisp and golden. Keep an eye on your first version so that it doesn’t burn.
11. Rest the kolokithopita for 20 to 30 minutes before serving. Cut into slices and serve warm or at room temperature.