Remove stems. This is optional. We actually often leave them in and just eat the leaves off of the stems.
Brush or rub the leaves with olive oil until well coated and sprinkle with sea salt to taste.
Place the leaves in a single layer on a large baking sheet.
Place in the preheated oven for 5-10 minutes or less. You will need to watch them closely and remove them as soon as they are crispy and barely browning.
Serve immediately or leave uncovered on the counter on a plate for up to 3 days.
Notes
Flavor variations: try adding spices like cumin and chili powder or ginger and garlic for a different taste.
If your leftover kale chips get soggy, toss them back in the oven for a few minutes to re-crisp them.