Cut the rice paper into quarters.
Slice the fish cake and onion into bite-sized pieces.
Add 200ml water, gochujang, red pepper powder, soy sauce, and sugar to a pan and bring to a boil.
Add onion and fish cake, then simmer on medium heat for 2 minutes.
Add the rice paper and cook on low heat for 1 minute.
When the tteokbokki thickens, add green onion and turn off the heat.
Plate and serve.