To make the filo parcels, preheat the oven to 180°C (350°F/gas 4). Grease an oven tray and get on with blitzing the pitted dates, vanilla and pistachios in a food processor or blender until you have a sticky mixture.
Take your filo pastry out of the packet and cut the sheets into strips (about 7 cm/3in thick) lengthwise.
Add a generous layer of custard and a layer of the date and pistachio mix on the right corner of the strip and fold diagonally to the left, enclosing the filling and forming a triangle.
Fold again along the upper crease of the triangle. Keep folding in this way until you reach the end of the strip.
Brush the outer surface with melted butter with a pastry brush, cover the whole of the top layer of pastry with the melted vegan butter/coconut oil, drizzle with maple syrup, then sprinkle with the chopped pistachios and brown sugar and place on the pre-greased oven tray.
Bake in the oven for 30 minutes, until golden brown.
Once the filo parcels are cooked, remove from the oven and serve hot with the no-churn ice-cream (if using), or leave to cool to room temperature before you serve.
For the Custard
Whisk the cornflour/custard powder, milk, turmeric, vanilla and sugar together in a small saucepan.
Bring to the boil on the stovetop while stirring until the custards thickens enough to coat the back of a spoon, then remove from the heat.