Clean the kale and remove the stems.
Heat the olive oil in a skillet and brown the pancetta and the onion for a couple of minutes.
Add the kale leaves, mix, and cook for a couple of minutes.
Add a spoonful or two of broth every now and then and cook over low heat until the kale is completely cooked - fork tender. It should take a little less than an hour.
Serve as a side dish, over toasted bread, or to season pasta.