This is a wonderfully, warm dessert to make any time of the year. In winter fresh granny smith apples and tinned plums can be used. In summer, you can use 100% fresh ingredients. Bonus points if you make the custard yourself (a good recipe for which can be found here).
The tartness of the plums and apples contrasts wonderfully with the smooth vanilla and spice flavour of the custard. For something a little more interesting, add some cinnamon and nutmeg to your custard before you add it to the pie.