Step 1: Preheat your oven to 300°F (150°C). Line a large baking sheet with parchment paper.
Step 2: Prepare the kale. Wash the kale thoroughly under cold water. Pat it completely dry with paper towels or use a salad spinner. This step is crucial for crispy kale chips; any moisture will steam the kale instead of crisping it.
Step 3: Remove the tough stems. Tear or cut the kale leaves into bite-sized pieces, discarding the thick, fibrous stems. Aim for pieces roughly 1-2 inches in size.
Step 4: Season the kale. Place the kale pieces in a large bowl. Drizzle with 1 tablespoon of olive oil. Using your hands, gently massage the oil into the kale, ensuring every piece is lightly coated. If some pieces still look dry, add the second tablespoon of oil, a little at a time, massaging it in. You want the kale to be coated, not drenched.
Step 5: Add seasonings. Sprinkle the salt, garlic powder, onion powder, and nutritional yeast (if using) over the kale. Toss gently with your hands again to distribute the seasonings evenly.
Step 6: Arrange on baking sheet. Spread the seasoned kale in a single layer on the prepared baking sheet. Do not overcrowd the pan; use a second baking sheet if necessary to ensure even cooking and crispiness. Crowding will lead to steaming.
Step 7: Bake the kale chips. Bake for 12-18 minutes, or until the kale is crispy and slightly browned but not burnt. Baking time can vary depending on your oven and the kale's moisture content. Keep a close eye on them, especially during the last few minutes, as they can go from perfectly crispy to burnt very quickly. You might need to rotate the pan halfway through.
Step 8: Cool and serve. Remove the kale chips from the oven and let them cool on the baking sheet for a few minutes. They will continue to crisp up as they cool. Serve immediately or store in an airtight container once completely cooled.