Warm a shallow pan with a splash of olive oil and sauté the sliced shallots until softened. Add the washed spinach with two tablespoons of water, turn the heat up high and cover. After a minute, stir the wilted spinach, then cook off any remaining liquid. Season with salt, pepper and a small handful of picked thyme leaves.
Line a 30cm round tart tin with parchment. Brush one sheet of filo pastry with olive oil and drape it over one half of the tin, then another sheet over the other side, allowing an overhang. Fold the overhanging pastry back into the pan to create a sturdy edge.
On your work surface, lay a sheet of filo pastry with the long edge facing you. Brush with olive oil, scatter with a little of the spinach mixture and dot with blue cheese. Lay another filo sheet on top and brush with oil. Using your fingers, roughly fold the pastry into a concertina, then coil it into a spiral, leaving it fairly loose. Transfer this to the centre of your tart tin. Repeat with the remaining filo, working outwards from the centre spiral until the tin is filled. Don’t pack it too tightly – the custard needs space to seep in. Gently tuck the sliced figs between the coils of pastry.
Whisk together the eggs, crème fraîche and milk until smooth, then stir in the Parmesan. Season with salt and freshly ground black pepper. Slowly pour the custard over the tart, letting it find its way into the gaps.
Bake at 200°C (180°C fan) for around 45 minutes, until the filo is crisp and golden. Remove from the oven, drizzle with honey and scatter over the remaining chopped walnuts. Serve warm, perhaps with a sharply dressed salad to cut through the richness.