Green papaya is the fruit of the papaya tree (Carica papaya) picked before it ripens, when the flesh is still firm, pale, and starchy rather than soft and sweet. Native to Central America and southern Mexico, papaya is now grown throughout the tropics, with major production in Thailand, the Philippines, and Vietnam.
Its firm, crunchy texture and mild, slightly tart flavor make it well suited to salads and slaws, most famously Thailand's som tam (green papaya salad), and to Filipino dishes like guinataang papaya, where it's stewed with meat in coconut milk. The fruit's enzymes also make it useful for tenderizing meat in marinades.
Choose papayas that are firm, heavy for their size, and evenly green-skinned; refrigerate and use within a few days for the best texture.