Recently I found a rare Southeast Asian cooking ingredient in the freezer section of my local Cambodian market: krasang fruit ក្រសាំង (pronounced “ga-sang”). The flesh and seeds of this fruit are used to sour soups and dips, much like the ways in which tamarind is used. The sourness of this ingredient is enhanced by a pleasant nutty crunch of its fenugreek-shaped seeds. To get more of a sense of what the fruit and tree look like, see images at the following Thai-language sites Farm Kaset and at the BGO Plant Database, and at the Khmer Online Dictionary.
Krasang is delicious when paired with chopped prahok (Cambodian fermented mud fish and kroeung see here for a post on these items, and even better when those are combined and cooked with chopped pork belly. This resulting dip is intensely flavored, and are well-matched with with raw or blanched vegetables. That is exactly how it is served at South Philly’s I Heart Cambodia restaurant (2207 S. 7th St), in the menu item “Krasang Prahok”.
So far in the U.S., I’ve only seen this fruit pickled whole in jars, and like the above image, frozen flesh and seeds without the dense woody skin. To give you some idea of the fruit’s dense skin, see a Thai language video on preparing that fruit of from Thai PBS–see the use of a hammer to open up the fruit at about 2:49.
There are several attractive recipes online that use this ingredient for cooking, but they are primarily in Khmer. That said, a few recipes in English can be found. Here is a video from Yummy Yummy – Asian Khmer Foods for two videos: a fried version of a prahok krasang dip and another version as “bok krasang”. Khmer-language pages are also worth checking out, at least for the images. Some of the recipes are uncooked like the above, like here, and others are roasted in banana leaves, and called “roasted prahok krasang” ប្រហុកដុតក្រសាំង. Finally, there is an over-the-top-version, again mixed with ground pork belly: chopping block-roasted pork prahok ប្រហុកចិញ្ច្រាំអាំងជ្រញ់. This seems to be trending in Cambodia where the dish also appeared in the Phnom Penh Post.