After numerous attempts at perfecting kale chips, I think I've got it. I start by marinading the kale in the olive oil for at least 20 minutes. By doing so, I have noticed that the chips turn out to be less oily. I bake my kale in a convection oven at 300degrees F. for 15 minutes or so but after the first 5 minutes I toss my kale constantly (meaning every 2-3 minutes). Unless your kale leaves are identically sized, chances are you are going to have to toss your kale. Add salt to taste once your kale crisps up. Enjoy!