Cut the rice cakes and fish cakes into bite-sized pieces.
Slice the onion and green onion diagonally.
Add cooking oil to a pan and stir-fry the onion and green onion.
Add the rice cakes and fish cakes and stir-fry together.
Pour in water, gochujang, red pepper powder, soy sauce, and sugar, then bring to a boil.
Boil until the rice cakes become soft.
Add eggs and cook until slightly runny (soft-boiled).
Transfer to a bowl and garnish with sesame seeds and chopped scallions to finish.