Step 1Seed and peel the squash. Slice it into 1/8-inch thick pieces.
Step 2Bring the Dashi to a boil in a medium saucepan, add the squash and cook for 2 minutes over medium heat.
Step 3In a small bowl, mix the miso with a few tablespoons of the hot Dashi. Add it to the saucepan. Return the soup to a quick boil, then remove it from the heat and pour the soup into individual bowls. Sprinkle each serving with chopped green onions.