Despite its straightforward ingredient list, several missteps can compromise the final dish.
The most frequent error is over-manipulating the tofu. Silken soft tofu curds contain delicate structural protein networks. Enthusiastic stirring breaks those bonds, releasing internal water into the stew and diluting the broth. Add the tofu late in the process, divide it sparingly, and let the boiling liquid circulate naturally around the curds.
Another common pitfall is substituting regular firm tofu. Firm tofu will not absorb the broth in the same way, nor will it provide the silky contrast that defines sundubu. If specialized tube-packaged sundubu is unavailable, Japanese silken tofu (kinugoshi) works as an acceptable substitute.
For vegetarian or vegan adaptations, drop the pork and clams entirely in favor of thick-sliced king oyster and rehydrated dried shiitake mushrooms. Replace the anchovy stock with a broth made by soaking dried shiitake and kombu in cold water for two hours, then bringing it to a brief simmer. Use a splash of fermented soy sauce or vegan mushroom sauce to supply the foundational salinity usually provided by fish sauce or salted shrimp.
