Soak the glass noodles in hot water to soften prior to cooking.
Bring 2 cups of water to a boil and add mushroom granules (or boil the unsalted vegetable broth).
Add scallion whites once water is boiling. Drain the glass noodles, then add them to the pot.
Cook until noodles are -almost- clear. They'll still be quite thin and will feel softer and almost nearly cooked.
Add the spinach and green scallion parts, then continue cooking until noodles are done and spinach is bright and wilted (about 2 minutes).
Feel free to add something like some chickpeas or fried tofu to the soup to absorb the flavour.
Add the toasted sesame seed oil and whisk in the miso paste (I just keep it in a large spoon and use chopsticks to stir it in the spoon until it dissolves).
Remove from heat, transfer to a bowl (or eat it straight out of a pot because... dishes) and garnish with some sesame seeds.
Enjoy!