1) Put a large shallow roasting pan or sheet pan in the oven and preheat the oven to 375°.
2) Rinse the kale and dry completely. Remove the stems and cut into pieces approximately 3 inches wide.
3) In a large bowl combine the kale with the olive oil, vinegar, salt and pepper, toss to coat the kale evenly with the mixture.
4) When the oven is up to temperature, carefully put the kale into the hot pan, spreading it out into one layer. It will sizzle. Roast for 10 minutes and then gently stir or turn the leaves over and roast for another 5–7 minutes, until the kale is crisp and dry but not too brown.