You will need the following...
2 tsp Dashi stock
3 tbsp Miso paste -white
1 block Firm Tofu
2 handfuls Spinach
2 Green onions
6 cups Water
I got everything from Wegmans, in the international aisle. WAL-MART DOES NOT SELL THIS STUFF.
You can add more veggies, or less. The base is the dashi stock. It either comes dried in a little jar like this (smells like fish food) or you can buy water based stock, but this works better for me. Or if you have any bonito fish hanging around throw em in a pot and make from scratch. Sooo..
To start, get about 6 cups of water in a pot and add 2 tsp of dashi stock to water.. Set to boil. While you are waiting for the stock to boil cut your tofu into 1-2 inch cubes. Be gentle with the tofu, it's very fragile.
Once your water is boiling, carefully add the tofu to the the stock. Let it cook for a few minutes until heated through. About 5-6 minutes should do.
And while you are waiting for the tofu to cook, dice up your spinach and green onions. Next you will want to add the spinach. I used baby leaf spinach, definitely not the right kind for miso soup. It wilts too fast and doesn't set well in the soup. Use bunched spinach instead. I will next time. I used about 2 handfuls here.
Get a separate bowl and add 1 and half to 3 tbsp of miso paste. It depends on the flavor you are looking for. Shiromiso has less sodium, so I used 3 tbsp in mine.
Then you will need to add 1 cup of your dashi stock to this bowl, and mix the miso paste well until dissolved.
Turn down your heat and carefully stir in the miso paste mixture. Once it's in let it cook for a minute or 2 and then turn off the heat and add your diced green onions. Try not to let the soup come to a boil after the miso paste has been added, I have read it will diminish or change the flavor if cooked at too high temperature.
Now just serve and enjoy. Very delicious, light soup. You can add more veggies if you'd like.