Pre-heat the oven to 200°C (fan)/220°C/425°F/gas mark 7.
Place the spinach in a large frying pan (or wok) and heat over a low-medium heat until wilted. You may need to add it in stages. Stir frequently so that it doesn't stick. If it does stick add a dash of water - but not too much as the spinach will release water as it cooks.
When all the spinach has wilted place it in a colander and leave it to drain and cool for a few minutes. Then place some sheets of kitchen towel on a board and spread the spinach over it. Cover the top with more kitchen towel and leave it to dry out while you get on with the rest of the recipe.
Heat the olive oil in a pan (you can use the same one you wilted the spinach in to save on washing up). Add the onion and leek and fry until soft. Add the garlic and cook for a few more minutes then set aside.
Heat 1 tablespoon olive oil in a small frying pan. Add the garlic and cook for a minute before adding the silken tofu, the lemon juice, the nutritional yeast (if using) and a pinch of salt. Break down the tofu with a wooden spoon and cook for a further minute or two. Taste and add more salt if needed. Set aside.
Return to the spinach. If it's fairly dry go ahead and chop it up. If it's still quite wet then use your hands to squeeze out as much water as possible. Finely chop and place in a mixing bowl.
Add the leek and onion mixture to the spinach along with the freshly chopped herbs, the spring onion, the lemon zest and the nutmeg. Finally add the tofu and mix everything well. Season to taste with salt and pepper.
Grease a 20cm round pie dish with olive oil. Uncover your filo pastry and remove one sheet. Place the rest underneath a clean tea towel while you work so it doesn't dry out. Place the sheet of pastry in the pie dish so that half of it is in the centre and half is hanging out. Brush it with oil then lay another sheet next to it so that it is is partially overlapping. Brush this with oil and repeat with the remaining sheets - it should look a bit like the spokes in a wheel.
Pour in the filling then fold over the filo pastry that is hanging over the sides - do the last one you added first. Brush the top of each with oil once folded.
Bake for 20-25 minutes or until golden brown. Serve warm or at room temperature with plenty of salad.