hi itk. i treat it like any other green. it's just a little more fibrous, so you need to discard most of the stem in the middle of the leaf. one way i make it is sauteed until it wilts in evoo with lotsa garlic, then i put in a little chicken stock, cover, and let it steam for a few minutes until tender.
it is also great in soups as it holds together better, not disintegrating into the soup.
one of my favorite fall soups is "irish 2 potato soup". i found a similar recipe called portugese kale and potato soup which used chorizo instead of ham. i liked the chorizo better, so here's my recipe for "irish/portugese 2 potato soup. (the amounts and times are approximate. i need to write stuff down when i cook)
5 garlic cloves, smashed and chopped
2 1/2 cups diced onions
3 cups sliced carrots
1/4 cup olive oil
1 pound russet (baking) potatoes (about 2 large)
8 cups chicken broth
2 pounds chorizo, cut into 1/4-inch pieces
1 pound kale, stems discarded and the leaves washed well, spun dry, and shredded thin (about 10 cups packed)
1 pound red potatoes
In a kettle cook the garlic, the onions, and the carrot in the oil over moderately low heat, stirring, until the vegetables are softened. Add the russet potatoes (peeled and cut into 1-inch pieces), broth, and/or enough water to cover, bring the liquid to a boil, and simmer the mixture covered, for 10 to 15 minutes, or until the potatoes are tender. While the potatoes are cooking, in a skillet cook the chorizo over moderate heat, stirring, until it is lightly browned. With a slotted spoon transfer the cooked potatoes to a blender, add about 2 cups of the cooking liquid and purée the mixture until it is smooth. Stir the purée potatoes into the broth mixture, add the chorizo, the kale, the red potatoes, cut into 1-inch pieces, and salt and pepper to taste, and simmer the soup, covered, for 20 minutes, or until the red potatoes and kale are tender.