Preheat your oven to 325 degrees F. Line two large rimmed baking sheets with parchment paper.
Wash the kale. Dry thoroughly, using a salad spinner, clean kitchen towels, or paper towels. Cut off the stalks.
Tear the kale leaves into bite-size pieces. After cleaning, you should end up with about 5 oz kale leaves.
Spread the leaves in a single layer on the prepared baking sheets. Generously spray them with olive oil and sprinkle them with kosher salt and garlic powder.
Roast the kale leaves until dry and crispy, 20-30 minutes. In my oven, it takes 22 minutes.
Some of the kale leaves will get crispy faster. So you can start checking on them after 20 minutes and remove the ones that are done to a plate. The very stubborn ones might take as long as 30 minutes to become truly crispy.