Whenever I feel like going "tanning" (that's my term for eating Kam Ja Tang), Huh Ga Ne, is always my go-to place. Food is great, service is fast and prices are affordable. Also, their Sam gyop sal and seafood pancake is pretty good too.
Now the only downside to this place this that it's ALWAYS packed so expect a 15-30 minute line up during dinner. Another thing, half of the tables are the low tables where one must seat cross-legged. So it might not be the most comfortable but it certainly is somewhat authentic.