Preheat the oven to 300 F.
Rinse the kale under cold water, then dry it thoroughly with a towel or a salad spinner. This is the step that decides whether the chips crisp.
Strip the leaves from the stems and tear them into chip sized pieces.
Put the leaves in a large bowl with the olive oil, apple cider vinegar and salt.
Toss with your hands, massaging the oil into every leaf so none are left dry.
Spread the leaves in a single layer on a parchment lined baking tray. Do not overlap them or they will steam.
Bake for about 10 minutes, until the edges are crisp and the leaves shatter when touched.
Cool on the tray for a minute before serving. They crisp further as they cool.
