Mix walnut oil with butter. Brush a thin coating on a piece of pastry. Place another piece on top with corners at a different angle, brush with the butter and repeat with one more piece. Place a spoonful of spinach mix in the centre, bring up corners of pastry and pinch in the middle to form a parcel. Repeat to make remaining parcels, then transfer to a greased baking tray. Brush parcels with remaining butter and oil. Bake for 20 mins until golden.