Soak rice cake in cold water, if it is frozen or have been refrigerated. If fresh and soft, do not need to soak.
Bring water and kelp to boil in a sauce pan. Boil on high heat for 10min. Discard the kelp.
Add the following into the sauce pan: gochujang, hot pepper flakes, garlic, sugar, mirin and black pepper. Stir and mix well until well dissolved.
Add the rice cake and onions. Simmer in medium heat for 10 min, stirring occasionally.
Add the fish cakes, soy sauce, and vinegar. (Add salt here:optional) Simmer for 3 min stirring constantly to avoild sticking on the bottom of the pan.
Add the noodles (optional) and simmer for 2-3min in low heat. Stir the rice cake but not the noodles.
Turn off fire and drizzle sesame oil, sesame seeds and scallions. Enjoy!!