2) Add the banana, allow to cool, and remove the cinnamon stick.
3) Melt the remaining butter and brush it on the filo pastry. Dust the filo with icing sugar and cut in half. Lay one sheet over the other, place the filling in the middle and roll up.
4) Place on a baking tray and bake in the oven for 30 minutes, or until golden brown. Remove and serve with the custard.
For the custard:
1) Bring the milk to simmering point slowly over a low heat.
2) Whisk the egg yolk, sugar and cornflour together in a bowl until well blended. Pour the hot milk on to the eggs and sugar, whisking continually.
3) Return the custard to the pan, add the vanilla essence and, over a low heat, gently stir until thickened. Serve immediately.