The basic ingredients are dashi stock, tofu, and spring onions.
Dashi stock
There are different types of dashi, mainly kombu (dried kelp), katsuo-bushi (dried bonito flakes), niboshi (dried small sardines) and hoshi-shiitake (dried shiitake mushrooms). Sometimes a combination of them is used.
The most common dashi is made with kombu and katsuobushi. It can also be prepared from instant powder, or in case of emergency substituted by vegetable stock.
Traditional miso soup
Ingredients
−900ml kombu and katsuobushi Dashi stock
−3 tbsp of Miso
−175gr of Tofu
−6 small Spring onion
Preparation
Bring water to boil and add the kombu and katsuobushi. Boil for a few minutes while removing the foam from the top. Stop the heat and wait for the ingredients to sink. Sieve through kitchen paper.
Dissolve the miso in a small cup of the stock. Bring the rest of the stock to boil and add the tofu cubes. Boil for a few minutes and remove from heat. Add the diced spring onions and the miso (this shouldn't boil or the bacteria in the miso will die) and serve.
Variations
Add sliced mushrooms and noodles (udon for example) for a change.