Per comments on original notes you can add some/all of the following - seasoning, garlic, leeks, pine nuts, cottage cheese. Also think fresh or dried dill would work well.
Made 2 of these using 1 pack of filo and 2 20cm tins. Added some leeks, aubergine and peppers which I fried gently first with cinnamon and dill. Plus a little Stilton. Think the filling would have been a little skimpy otherwise. Next time some chopped nuts (for texture would be good). Stored the uncooked 2nd pie in the fridge covered with moist kitchen towel. The cooked pies were tasty hot and cold - held together well when cold. Note for me - trivet not necessary in micro oven as top crisped too quickly.