In a large Dutch oven, add the sesame oil and heat over medium.
Add the yellow onion, ginger, and garlic and cook until softened, about 5 minutes. Then add carrots and cook an additional 5 minutes
Add the mushrooms and continue to cook until softened and lightly browned, another 7 minutes or so. Season with salt and pepper to taste. The soup is salty due to the miso and vegetable stock so be mindful when adding salt
Add the miso paste and cook a minute or so.
Whisk in the stock and bring to a simmer over medium-high heat. Season again with salt.
Once simmering, add the water, kombu, zucchini, kobocha squash and continue to simmer for another 25 to 30 minutes.
During the last 5-10 minutes, add greens and stir to combine. Add more water as needed to cover and simmer until the squash is tender. Remove Kombu and cut it and add back in before serving
Season once last time to taste and serve hot.