Preheat oven to 180°C (350°F). Carefully press pie dough into a 30 x 20 loose-based tart tin and trim any overhang. Refrigerate while you prepare the filling.
Spread nuts on an oven tray and bake 8 minutes until just-toasted. Tip into a large bowl and set aside to cool
In a blender or food processor pulse the pitted dates, syrup, oil, salt and vanilla until smooth. Add the eggs and blend again to incorporate. Pour the caramel into the bowl with the toasted nuts and stir well.
Tip filling into the unbaked pie shell and place on a tray to catch any drips. Bake 30 minutes, then cover loosely with foil to prevent over-browning, and bake a further 10-15 minutes until firm on top and puffed in the centre.
Cool completely, overnight if possible, to allow filling to set. Cut into small slices to serve.
Pretty much any combination of nuts will work here, feel free to use your favourites!
You can also make this as a traditional pie in a standard 23 cm (9 inch) pie tin, or any other rectangular tin with a similar volume.
You’ll need 1 ½ square sheets of store-bought short-crust pastry to line a 30 x 20 cm tin.