Soak the wakame in a bowl with 120 ml cold water until soft.
Drain (reserve the water), cut into small pieces and set aside. Peel the fresh ginger and finely mince half of it. Finely grate the other half in a small bowl and keep for later. Chop the spring onions and cut the tofu into small cubes.
In a frying pan, sauté the white part of the spring onions for 1 minute in the sesame oil, then add the garlic, ginger and salt. Sauté a little longer, add the hot water, tofu and set-aside wakame and cover. Bring to the boil, then lower the heat and simmer for 4 minutes. Remove from the heat.
Pour approximately 60 ml of hot water into a small bowl.
Add the miso and purée really well with a fork, until completely dissolved. Pour back, cover and let sit for 2–3 minutes. Take the grated ginger in your hand and squeeze it to release the juice directly into the hot soup. Discard the remaining ginger pulp. Add the chopped spring onion greens, parsley and lemon juice and serve immediately