Preheat the oven to 275 degrees. Fill a large bowl with water and add kale. Swish around to remove any dirt; drain. Dry thoroughly using a salad spinner or a clean kitchen towel.
Tear the kale leaves into 1” – 2” pieces, discarding the ribs, and place in a large bowl. Drizzle with olive oil and toss with your hands until evenly coated.
Arrange the leaves in a single layer (with NO overlap) on ungreased cookie sheets. Rub each leaf gently between your fingers as you work to ensure each is covered in oil. Sprinkle with salt and pepper.
Bake for 18 to 20 minutes or until leaves are crispy.
Kale: Any kale works here: Common curly, Lacinato (aka Tuscan or Dinosaur kale), red or Redbor, or Siberian kale. Be sure to remove the woody stems before tearing the leafy greens into "chip"-size pieces. The bags of chopped kale always include stems. The weight of a bunch of kale varies, but here are some guidelines. The bunch of curly kale pictured in this post weighed 9 ounces, then 6 ounces after I removed the toughest stems. After tearing it into small pieces, I had 12 cups of uncooked kale. This cooked down to 8 cups kale chips.
Yield: 12 cups uncooked kale cooks down to 8 cups kale chips. Because they are so light and thin (shatteringly crisp), I like 2 cups kale chips per serving (4 servings).
Storage: Store in an airtight container or a zip-top bag at room temperature for up to 4 days.
Your pan plan: Kale cooks down to a fraction of its original size. Plan on 2 to 3 sheet pans per bunch of kale (depending on the size of the bunch and the size of your pans). I do about 4 cups uncooked kale per baking sheet.
No overlap: The most important step for super-crispy vegetable chips? They must be arranged in a single layer. Overlapped chips causes them to steam and they won't be crispy.