In a large pot or Dutch oven, heat olive oil over medium heat.
Add onion and cook until softened, about 5 minutes.
Add garlic and ginger and cook for another minute until fragrant.
Add carrots, fennel, cremini mushrooms, and shiitake mushrooms. Cook until softened, about 5-7 minutes.
Pour in water, add reishi mushroom powder, miso paste, allspice, and thyme. Bring to a boil, then reduce heat and simmer for 20-25 minutes.
Add kale and cook until wilted, about 5 minutes.
Season with salt and pepper to taste.