Cut the chewy konjac rice cakes, fish cake, and onion into bite-sized pieces.
Add a little cooking oil to a pan and sauté the onions.
Add the fish cake and konjac rice cakes and stir-fry together.
Add gochujang (Korean chili paste), chili powder, soy sauce, water, and oligosaccharide syrup, and mix well.
Let the sauce simmer for 5-8 minutes so the rice cakes and fish cake absorb the flavors.
Transfer the finished tteokbokki to a serving dish and sprinkle with sesame seeds.