The polenta is based on a recipe from Passionate Vegetarian. The author says it's an old Tuscan peasant recipe.
Braised greens with tofu, cashews and raisins
The whole vegetable part takes about 15-20 minutes including prep time, so plan accordingly so you can have the veggies and polenta finish cooking about the same time. The kale part of the recipe is based on a recipe that I think was from the NY Times. I'm not sure though.