Kale soup is a type of hot soup that features kale, though most recipes also include other vegetables. One of the most famous versions is Tuscan ribollita, a nourishing kale-and-white bean soup that's easy to make completely vegetarian.\nKale is a leafy green which is actually a close relative of cabbage. Kale originally grew around the Mediterranean region, with evidence of cultivation dating back to around 2000 BCE. Once a dietary staple of the Ancient Greeks and Romans, kale has taken a star turn as a “superfood” on contemporary dinner plates thanks to its hearty flavor and ample nutrition. Kale is high in vitamin A, vitamin C, and vitamin K.\n\nThere are several different types of kale, all of which taste great in soups. \n\n1. __Curly kale__: The most common type found in supermarkets and farmers markets is curly kale, which has a unique appearance with wavy, curled leaves. It is about the same color as broccoli. This type of kale has a bitter, peppery flavor when eaten raw, and holds up well to sautéing and other cooking methods.\n2. __Tuscan kale__: Also called lacinato kale or dinosaur kale, Tuscan kale is recognizable by its smooth, dark green leaves. Tuscan kale is milder than the curly variety and can be eaten raw in a kale salad or wilted in a soup.\n3. __Baby kale__: Baby kale leaves come from young kale plants and are more delicate in flavor and texture than mature kale. Baby kale is best eaten raw in salads but is tough enough to be sautéed like spinach.\n4. __Purple kale__: You might occasionally come across purple kale, or Redbor kale. This type of kale is bright purple with leaves that closely resemble curly kale—though not as tightly curled. Slightly sweeter than curly or Tuscan kale, purple kale adds color to any dish and handles cooked and raw preparations with ease.\nYou can add kale to almost any soup recipe—it tastes great with lentils, farro, and Italian sausage—but here are three traditional versions to try.\n\n1. __Ribollita__: Ribollita ("reboiled") is a Tuscan vegetable soup made with cavolo nero (aka Tuscan kale or dinosaur kale), bread, onions, carrots, garlic, celery, white beans, and tomatoes. Its name comes from the fact that it was often made from last night's minestrone heated up the next day with leftover bread.\n2. __Caldo verde__: Caldo verde ("hot green") is a Portuguese soup made from potato and kale or other dark leafy greens like collard greens or mustard greens. In the seventeenth century, the Portuguese brought this soup with them to Massachusetts, where it remains popular.\n3. __Grünkohlsuppe__: Grünkohlsuppe ("green kale soup") is a German soup made from kale, potatoes, and smoked pork sausage.\nTuscan kale soup is a flavorful, healthy soup packed with veggies.