Apparently using a thermomix rather than a blender or food processor to pulverise the ingredients in lui cha yields the best results. That's why three of my relatives visited my grandma with plastic bags filled with stalks kilos of shu zai choi (potato leaves?) and a mountain of mint.
We assembled a factory line on the driveway and lined it with greens, stools, tubs and baskets. Once the potato leaf stalks were almost bare, my grandma went to roast peanuts, whilst I became alpha-leaf-washer, scurrying back and forth with baskets of leaves for the leaf-wilting-auntie, whilst my mum and her cousins continued to pluck bunches and bunches of mint.
The most exciting job was definitely being in command of the thermomix, since no one else knew how to use it. Crushed white pepper corns and tea leaves into a fine powder before whizzing roasted peanuts and sesame seeds into a paste. The next bit is where the fun really began. Alongside the powder and paste were a portion of the wilted potato and mint leaves. Within seconds it became a delicious, aromatic, smooth green mixture. Too bad we were working so productively I didn't get a chance to smother some on my camera.
Unfortunately, we won't be around when they serve it, but my grandma has tupperware filled with the stuff in the freezer. Her version includes garlic, dried anchovies and shrimp and another type of herb. I'll try it out the soupy way before I leave, but I reckon it'll work just as nice spread on a soda cracker or on a piece of bread.