Ingredients of miso soup can vary depending on the recipe but two ingredients that are always present - no matter what recipe it is - are miso paste, and seaweed (wakame and others). You can also have tofu, scallion, roasted sesame seeds, and shitake mushrooms, among other ingredients. I've actually written a hub on how to make miso soup... Miso soup is very delicious and refreshing. It can be eaten hot or cold. Tastes great either way.