Preheat the oven to 120 celsius (250 fahrenheit) and line 2 large baking trays with baking paper. Remove the kale from the stalk and tear the leaves into pieces, keeping in mind that the kale will shrink when baked. Wash and dry well in a clean tea towel. It's important the kale chips are dry before baking otherwise your chips won't be crisp. Don't skip this step!
Toss the kale in the olive oil and a sprinkling of salt until it's coated in the seasoned oil. Go easy on the salt here as you can always add a little more after baking if they aren't seasoned enough.
Divide the kale between the trays and ensure that the kale is not overlapping to ensure maximum crispiness when baked. Bake for 10 minutes before turning the leaves over and baking for another 10 to 15 minutes.
If not eating immediately, cool completely before storing in an airtight container for up to a week. Storage time will depend on humidity, however I've been able to store them for a week and still be perfectly crisp.