Put one cup of the water or broth in a saucepan and turn on medium heat
Add the ginger, astragalus, seaweed, mushrooms, chopped vegetables, scallions and simmer about 5 minutes until the vegetables are soft,. Turn the heat to low.
Remove astragalus
Put Miso into a small bowl, add a spoonful or two of broth and mash into a paste. Put Miso mixture into pot
Turn off the stove
Stir in tahini
Add remainder of water or broth to saucepan
Stir and serve.
Garnish with scallions, chive or basil