Put custard powder, tapioca flour, sugar and milk into a medium sized pot.
Whisk together, then heat over a low heat until very thick, whisking frequently. You may need a spoon or spatular to get into the corners where the whisk can't reach.
*If its taking a long time to thicken you can turn up the heat but watch it and whisk constantly, it may thicken fast. You need to cook the custard for long enough to cook out the 'floury' taste of the custard powder and tapioca flour
Take off the heat and cool, then whisk in cream and vanilla essence. You will need to whisk whisk whisk to mix properly until smooth
*If you're having trouble getting the lumps out pass the custard through a strainer.
Chill the custard ice cream base until cold.
Line your deep sided dish with cling wrap, leaving a wide edge hanging over each side. You may need to criss cross the cling wrap to get full coverage over the dish.
If you are using a self refrigerating ice cream churner turn on ten minutes before churning to chill, other wise take your bowl out of the freezer just before churning.
Churn ice cream. It will be the consistency of soft serve when done.
Put churned ice cream into dish lined with cling wrap. Flatten out the top, then place a layer of cling wrap on top. Freeze over night. You need very firm ice cream.