Grate the courgette into a large bowl. If they are particularly juicy, wrap in a clean tea towel to remove the excess moisture.
Add the spinach leaves, crumbled feta, grated parmesan, beaten eggs, pesto, grated garlic, dried mint and seasoning. Give everything a good mix and tip into the baking dish.
Taking the filo sheets, cut them in half into squares. Then scrunch each piece and place on top of the mixture in the dish. Continue until you have covered the surface - they should sit snuggly together and you shouldn't be able to see the pie filling underneath.
Brush the pastry with the melted butter and place in the pre-heated oven for 25 minutes. Serve golden brown with a crisp green salad on the side.
Notes
Use can use just courgette (500g) if you wish and forget about the spinach.