Prepare salmon broth by placing the salmon heads in a large pot and add about a gallon of water. Use enough to fully cover the heads. Bring to a boil and then turn down to a simmer for 4 hours. Cool and strain. (The salmon heads can have some lovely meat on them, so take out the tasty pieces and set aside. The rest can be gotten rid of. This will make more than what is called for in the recipe. Freeze what you don’t need now.)
When you’re ready to prepare the soup, put the shiitake mushrooms into a bowl and pour boiling water to cover the mushrooms. Let soak for 20 – 30 minutes. Remove mushrooms and set mushroom broth aside.
Put strained salmon broth in a large pot. Add mushroom broth and clam juice.
Slice shiitakes and white mushrooms.
Wash miner’s lettuce or spinach.
Slice scallions lengthwise into multiple pieces and then into 1 ½” slivers.
Cut shrimp or faux crab into bite-sized pieces.
Put all of the prepared ingredients into the pot containing the broth.
Prepare the soba noodles on the side according to the package directions. These don’t take as long as Italian style pasta, so keep a close eye on them.
When the soba is ready, put the desired amount in a large bowl with about 1 Tbsp. of miso (less or more to taste depending on the size of your serving.
Ladle the soup into the bowl and stir gently to incorporate the miso. Enjoy!