This dish can be served either hot or cold (see ‘What are Taiwanese cold noodles’ if you want to hear the technicalities). I personally prefer them hot, in which case assemble the bowls as soon as the noodles have finished cooking. If you prefer them cold, just wait until the noodles have cooled. You could use the time to julienne some cucumber and carrot, which add a nice crunch to the cold version.