In a large pot bring 4 cups of salted water to a boil over high heat. Add kale and boil until tender, about 10 minutes. Drain in a colander, then refresh under cold running water, and drain well.
In a large skillet, heat olive oil. Combine bell peppers, onion and garlic and saute for 3-5 minutes. Add 1/2 cup water and 2 tablespoons balsamic vinegar. Bring to a boil. Lower heat and simmer until water evaporates and onion is softened, about 5 minutes. Add tomato and simmer for 5 minutes. Stir in cooked kale and cook for 15 minutes more. Season to taste with salt and pepper. Garnish with crostini toast.
Photo by Maryam Nikkhah, vcfoto.com