In a medium-sized pot, bring the water to a boil. Add the buckwheat, reduce the heat to low, cover, and simmer for 15–20 minutes, or until the water is absorbed and the buckwheat is tender.
Meanwhile, heat the vegetable broth in a separate pan over medium heat. Add the butternut squash, mushrooms, kale, and basil. Cook, stirring frequently, for about 15 minutes, or until the squash is tender.
Divide the cooked buckwheat between bowls. Top with the vegetable mixture and serve.