Put 4 cups of water, 7 large dried anchovies, heads and guts removed, and 1 piece of dried kelp, about 6 × 8in / 15 × 20cm, in a shallow pot. Boil uncovered over medium-high heat for 15 minutes.
Mix ⅓ cup of gochujang, 1 tablespoon of gochugaru, and 1 tablespoon of sugar.
Remove the anchovies and kelp. Add 450g of cylinder rice cakes, the sauce, and 3 scallions, cut into 3in / 7.5cm pieces.
Once boiling, stir gently for 10-15 minutes, until the rice cakes are soft and the sauce is thick and glossy. Add a little water if the rice cakes are still firm.
