To make nam phrik nam phak, the villagers of Ban San Thang Luang, in rural Chiang Rai, take freshly picked yu choy greens and dry them in the sun for a day, ferment them for as many as two nights, and boil them for another hour before finally pounding them with spices and toasted chiles in a mortar and pestle. Those of us living in less tropical climes can approximate the sun-drying process by spreading the greens out onto several racks and placing in a dehydrator or a low oven, stirring occasionally, until they reach the proper dryness.
A spice related to Sichuan peppercorn and prickly ash, makhwaen seeds are commonly used in northern Thailand but tricky to find in the U.S. Christian Leue of New York-based spice purveyor La Boite suggests substituting a mixture of sansho peppercorns and orange zest to approximate their bright, piney, floral fragrance and numbing sensation.
This recipe is adapted from Austin Bush's The Food of Northern Thailand.
