Soak the rice cakes in cold water for 10 to 20 minutes if hardened. Skip if using fresh rice cakes.
Mix all the sauce ingredients well in a bowl. Cut the chicken into bite size pieces. Mix with the sauce (reserving one tablespoon if you’re going to make fried rice at the end) and marinate while preparing vegetables.
Cut the chicken into bite size pieces. Mix with the sauce (reserving one tablespoon if you’re going to make fried rice at the end) and marinate while preparing vegetables.
Cut the sweet potato in half lengthwise and then thinly slice crosswise and slightly diagonally. Cut the cabbage, kkaennip, and scallion into small pieces.
Heat a pan over medium high heat. You can add a tablespoon of oil if you want, but this is not necessary. Add the chicken, sweet potatoes, rice cakes, and cabbages. Cook for 5 minutes, stirring occasionally. Lower the heat if the ingredients (especially the rice cakes) stick to the pan. The steam from the vegetables should keep them from sticking to the pan. You can also add a couple spoons of water if the pan gets too dry.
Add the kkaennip and scallion and cook for another 3 to 4 minutes until the rice cake and the sweet potato pieces turn soft. By then the chicken should be cooked through.
Optional Fried Rice: Add the rice to the pan along with the reserved sauce and sesame oil. Stir constantly until everything is well incorporated and the clumped up rice is broken up, about 5 minutes. Scrape up the flavorful brown bits from the pan while stirring. Mix in the dried seaweed and sesame oil.