Cavolo Nero, or Black Leaf Kale:

Black Kale Soup - Zuppa di Cavolo Nero
This is an extremely simple winter soup that will bring warmth and happiness overtones the kitchen. My Italian source simply listed ingredients, so I have given amounts; feel free to adjust them to suit your taste.

Kale Farinata - Farinata di Cavolo Nero
A farinata is a thick porridge, usually made with vegetables, broth, and finely ground corn meal. This recipe is Tuscan, from the mountains, and is classic winter fare; it was made as a one-course supper, with the leftovers being sliced, grilled, and eaten for breakfast, perhaps with a glass of wine.

Kale Farinata II - Farinata Col Cavolo Nero II
A farinata is a thick porridge, usually made with vegetables, broth, and finely ground corn meal. This is an old Tuscan recipe, and a fine example of frugal Italian country cooking. It supposedly will serve 6-8 as a one-course meal with a tossed salad, though in my experience this estimate is optimistic: Expect people to demand seconds.

Polenta and Black Leaf Kale - Polenta e Cavolo Nero
Though Italians generally associate cavolo nero with Tuscany, it's grown throughout the land, and this recipe is from the Valle d'Aosta. It's generally served as a one-course meal.

Kale on Toasted Bread - Cavolo Nero Con le Fette
Kale on toast is extremely good, and since this leans in that direction, some might also identify it with bruschetta.

Kale in a Casserole - Cavolo Nero in Casseruola
What does winter cold bring to mind? Cabbages, the classic winter vegetables. Though I generally associate kale with Tuscan cooking, it does also grow in other parts of Italy, including Lombardia, which is where this recipe hales from.

Farro Soup with Kale - -Zuppa di Farro col Cavolo Nero
Kale and farro are beautifully paired, and since kale is at its best when its leaves have felt the bite of frost, so this is a winter recipe.

Ribollita & Minestra di Pane
Minestra di pane and ribollita are two of the best uses for sliced Tuscan bread (crusty, firm of crumb, and without salt) I have ever come across. Tuscans make this hearty winter soup (Ribollita is Minestra di Pane reheated) with cavolo nero, black leaf kale.

Roberto Giannini's Ribollita
An old, old recipe for Ribollita that Roberto's ancestors have been handing down for generations. But a nice one, too.

Hearty Soup with a Ham Bone - Zuppa Con L'Osso del Prosciutto
To make this soup you will need to cozy up to a butcher or delicatessen owner who has a prosciutto bone; in its absence substitute for it with the bone from a well seasoned and cured ham, such as one from Smithfield. It’s a slow-simmering soup that’s perfect for warming the whole house.

Kale Soup over Garlic Toasted Bread - Zuppa di Cavolo Nero su Fette di Pane
This soup is from Versilia, the coastal region north of the Arno, and involves considerably more garlic than one encounters inland.

Last Note:
Kale leaves can also be used as wrappers: Blanch them briefly in lighly salted water, use them to wrap whatever filling you have in mind, for example cubes of cheese (bake these), shrimp or prawn tails (bake them), fish filets (bake or braise), chicken breasts (bake or braise), or even something like risotto (braise).

General information about Kale, or Cavolo Nero