In a skillet, sauté onions in olive oil over medium heat until soft. Be sure to choose a skillet or large pot that has a lid and is big enough to hold the entire bunch of kale before it wilts.
Add the kale, wine and broth. Stir and cook the kale until it has wilted to half its volume.
Place a lid on the skillet or pot and turn the heat down to low and allow the kale to simmer in the liquid for 30 minutes, stirring occasionally. Add salt to taste and red pepper flakes for a bit of heat. Serve and enjoy!