Traditionally, kale (German name: Grünkohl) is cooked with Mettwurst or Pinkel, which is a specific German sausage that I haven't managed to get here in the US. You can substitute it for Kielbasa sausage or, as I usually do, bacon.
This recipe is for 4-6 people.
2 bunches of kale
1 large sweet onion
1 lb. sliced bacon
1/2 bag of unseasoned, diced hashbrown potatoes, or 2 large Russet potatoes
1/2 cup of water or broth
salt and pepper to taste
Thoroughly wash kale. I usually only use the upper half of the stems because the lower, thicker part is very woody and takes too long to cook. So I take the leafy parts off the lower stems and use them, and throw the lower stems themselves out - but of course that's up to you. Chop leaves into small pieces and set aside.
Cut sliced bacon into 1/2-inch pieces. Heat up large pan and fry bacon till crisp. In the meantime, chop the onion and add when the bacon is done. Saute onion until it gets glassy (I'm sure there's a cooking term for that, but whatever.)
Add kale by the handfuls and stir in between to make it wilt before you put more in. When the concoction gets too dry, add a little cold water or broth (vegetable, beef, chicken, whatever you like). Rule of thumb is that there should be a 1/4 inch of liquid at the bottom of the pan at all times - until the very end, when you want it a little drier.
Simmer kale, onion, and bacon on low heat for about 20-30 minutes. Then add the hashbrowns (my way of saving myself a bunch of work) or the finely diced Russet potatoes. Cook another 30 minutes or until potatoes are tender enough to squish against the pan wall.
That's it - enjoy! Even people who are very skeptical about kale love this meal... and as usual, no leftovers here!