Heat a little oil in a saucepan and sauté the onion and garlic for a couple of minutes.
Add the spinach along with the spring onions and let it heat through until the spinach wilts, - season with a little salt and pepper.
Tip the spinach mixture into a colander and let it drain well. It helps to press it with the back of a spoon, - so you squeeze out as much liquid as possible.Let it cool slightly before you stir it into the egg mixture.
Whisk the eggs together in a bowl, then stir in the Greek yoghurt, parsley, nutmeg and crumbled feta. Season with plenty of freshly ground pepper and a little salt, and fold in the cooled spinach mixture.
Line the base of a springform tin with baking parchment and brush both the sides and base with olive oil.*I recommend a springform tin between 20-24 cm in diameter.
Brush the top of each filo sheet with oil, – but do it one sheet at a time as you build up the pie. It is easiest done with your hands, but you can also use a pastry brush, or alternatively an oil/baking spray.
Lay the first filo sheet in the springform tin and press it out against the sides, – letting the rest hang over the edges (the sides will be gathered in over the pie at the end). Don't worry if the pastry tears a little here and there, – there are 6 more layers to come;-)
Continue until all the sheets are used, – and remember to brush the top of each sheet with a little oil before laying the next one on top of it in the tin.*Rotate the sheets a little for each layer so they sit differently in the tin. The sheets are usually rectangular, so by turning them slightly between layers you make sure they can reach all the way over the pie when it is closed.*See the photo below the recipe, – it shows what the tin looks like once all the sheets are lining it.
Pour the filling into the tin and smooth it out with a spoon.
Fold all the sides in over the filling. Do it in layers, and feel free to leave them a little rustic.
Once the pie is closed, brush the surface with oil, or spray it with a little oil/baking spray.
Bake the pie in a preheated conventional oven (top and bottom heat) at 170°C for about 45 minutes. Always keep an eye on it as it bakes, – your oven may give more heat from the top, in which case the pie should go lower in the oven.*I put the pie on a rack in the middle of the oven, but if you find it is already quite a dark golden after 30 minutes, you can move the rack lower down.
Let the pie rest for about 10 minutes before opening the springform tin.
Serve the pie either on the base of the springform tin, or slide the baking parchment onto a plate. I would not recommend trying to remove the pie from the parchment – as filo pastry is naturally very fragile.
Sprinkle with finely chopped parsley before serving, – and cut the pie with a bread knife.