Ice cream bean is a South American fruit tree sometimes seen for sale in Nurseries or growing in Perth and surrounding areas, but it's not common in WA and there's limited local knowledge regarding the species. No real development work has been done on them globally, so there are no named cultivars, and if you manage to source one here it will be a seedling, inevitably labelled I. edulis.
The species name comes from the Latin word for 'edible' and the plant you acquire may ultimately produce edible fruit. The problem is that the genus consists of around 300 species and about 50 of these produce edible fruit. The following pictures (taken from Amazon River Fruits: Flavours for Conservation, Professor N. Smith, R. Vasquez & W.H. Wust (2007), Missouri Botanical Gardens Press, 272pp), illustrate just some of the variation in fruit forms of different edible species. See also a review of this book: the link is in the Essays list. The genus is divided into 14 sections with I. edulis in section 12. Most of those shown in the pictures are in other sections, but as might be guessed from the similar pod morphology, I. ingoides is also in section 12. So with all these other possible confounding species that could have slipped into the original sourcing, propagation and marketing chain somewhere, is it possible to firm up your confidence that your new plant is what you expect it to be?
With this level of diversity in the genus, the answer to being able to nail it down precisely to edulis is "no", short of using a full taxonomic key. But you can fairly easily exclude many possibilities with a few simple checks:
Correct identification is not purely academic as many other species don’t taste quite as nice. Best to be a little cautious when you buy a plant from retail outlets. Often in these matters of possible confusion, you can cut through the dilemma of whether you're spending all your management efforts over some years on raising the real McCoy is to taste a fruit from a local tree satisfying at least the above criteria, obtain scion material and graft onto a seedling. Alternatively you can germinate seeds from such a plant but you may have to wait a little longer for fruit, they may not be exactly true to type and the tree will want to be bigger. The final picture is from a tree growing here in the Perth suburbs showing a pod that clearly is not I. edulis.