Wash the kale thoroughly under cold running water to remove any dirt or debris. Pat it completely dry with paper towels or a clean kitchen towel—this is crucial because any excess moisture will cause the chips to steam rather than crisp up. Remove the tough central stems from each leaf by holding the stem at the base and stripping the leafy portion away with your other hand. Tear the leaves into roughly 1-inch pieces, discarding the stems.

In a large bowl, combine the olive oil, salt, garlic powder, and black pepper. Add the prepared kale pieces to the bowl and toss gently but thoroughly with your hands, making sure every piece is lightly coated with the oil and seasonings. I like to massage the kale gently as I toss it—this helps the seasonings adhere better and ensures even cooking. Don't over-coat; the kale should glisten lightly but not be dripping with oil.

Preheat your oven to 300°F and line a large baking sheet with parchment paper. Spread the seasoned kale pieces in a single layer on the prepared pan, making sure they're not overlapping or piled on top of each other—they need direct contact with the heat to crisp properly. Bake for 20–30 minutes, stirring gently halfway through cooking to ensure even crisping. The chips are done when the edges are darkened and the leaves are completely crispy and brittle; they'll continue to crisp as they cool, so don't wait until they're overly dark in the oven.

Remove the kale chips from the oven and let them cool on the baking sheet for a few minutes. They'll finish crisping as they cool. Once cooled completely, they can be eaten immediately or stored in an airtight container for a few days.