Tteongmanduguk (떡만둣국), translates literally to rice cake (떡) dumpling (만두) soup (국). Its very often eaten in Korea on lunar new year. Also see https://en.wikipedia.org/wiki/Mandu-guk

Its roughly made by making an anchovy broth, adding large green onions (대파 [dae-pa] in korean, different from normal green/spring onions, but normal green onions are fine to use), a bunch of garlic, rice cakes, and then dumplings along w/ soup soy sauce and salt to taste and boiling for a bit. At the very end, you can mix up an egg like for scrambled eggs and pour it into the soup just before eating along w/ sesame oil. For decoration (definitely not required) I cut up the gim used for gimbap (different from the kind you might eat in a snack pack, less brittle) and put it on top w/ sesame seeds.

The recipe i followed in is Korean (for those interested: https://m.blog.naver.com/ejs2122/223090632970) but this recipe is also good and has translations attached.

The end result was really tasty and I will definitely do it again some day, but I will say two things I would do differently next time:

1. Use fewer egg. I used two but one egg is plenty. You can probably tell from the picture there is a lot of egg.
2. This soup doesn't take to storage well. The dumplings and rice cakes will quickly get very soft and mushy overnight it the fridge. My recommendation, is to make only enough to eat, or removing the dumplings and rice cake from the soup and storing separately.