Heat oil in a medium soup pot and sauté the onions and garlic for 8 to 10 minutes. Remove shiitake and maitake from soaking water, reserving soaking water. Sauté for 3 to 5 minutes. Add the mushroom soaking waters, water, butter beans, squash and black pepper. Cover and bring to a boil. Reduce the flame to medium-low and simmer 20 minutes. Add the sea salt and cook another 10 minutes. Add the kale, adjust the seasoning if needed, and simmer another 5 minutes. Serve.
5g fat (20% calories from fat),