Preheat oven to 180°C, place a wok on a medium heat and spray with low calorie spray.
Add the onion and garlic to the pan and sauté until softened.
Once cooked add to a large bowl, then add the spinach to the pan and place a large pan lid over to wilt the spinach.
Tip the spinach onto a clean tea towel and squeeze out as much of the excess water as possible.
Add to the bowl, then crumble in the feta, grate in the parmesan, add the lemon zest, oregano, parsley and eggs. Mix until fully combined.
Lightly spray a 20cm round springform tin with low calorie spray. Place 1 sheet of filo pastry into the tin and using a pastry brush, brush the filo with the melted butter. Repeat with another sheet, allowing part of the sheet to over hang over the sides of the tin. Repeat until all the sheets are used and there’s overhanging pastry, all round the tin.
Spoon the filling into the prepared pastry.
Fold the overhanging pastry back over the filling, brushing with butter again, ensure the filling is completely covered.