We just got back from Alaska, and I was looking up Soapberries. I'd never heard of Soapberry Ice Cream until today.
Here's what I found out:
The Canada Buffaloberry (Shepherdia canadensis), also known as Russet Buffaloberry, Soopolallie, Soapberry, or Foamberry, is one of a small number of shrubs of the genus Shepherdia bearing edible red berries. One recognized form however bears yellow fruits. The berries have an extremely bitter taste.
Fruits are extensively collected by some Canadian First Nations peoples such as Nlaka'pamux (Thompson), St̓átimc and Secwepemc (Shuswap) in the province of British Columbia. The bitter berries are not eaten directly but rather processed as sxusem ("sxushem") or "Indian ice-cream". Branches bearing fruit are hit with a stick and only the very ripe fruits that fall off are collected. A clean mat or tarpaulin is placed below the bush for collection. The berries are later placed into a great bowl that is absolutely free of oil or fat and are mixed with some sweet fruit such as raspberries. The mixture of berries is crushed and vigorously beaten in the manner of whipping cream in order to raise the typical foam of the sxusem confection. Sxusem has an agreeable blend of sweet and somewhat bitter tastes, possibly comparable to that encountered in sweetened coffee. The substance is believed by the First Nations peoples who prepare it to have many healthful properties, but the saponin chemicals making up the foam may also cause gastrointestinal irritation if consumed greatly. Native theme restaurants in British Columbia have occasionally had sxusem on the menu in recent years.
Persons reading about saponins should be forewarned that unrelated plants in the genus Sapindus, which produce highly toxic saponins, share the common name soapberry with the edible Canada Buffaloberry. References to Sapindus "soapberry" toxins should not be misattributed to Canada Buffaloberry.
The common name of the plant in British Columbia is soopolallie, a word deriving from the historic Chinook Jargon trading language used in the North American Pacific Northwest in the 19th and early 20th centuries. The name is a composite of the Chinook words for soap (soop) and berry (olallie).(Wikipedia)
Mix 1 cup berries with 1/4 cup water and 4 tablespoons brown sugar, until all the berries have dissolved into a stiff pink foam.