Preheat oven to 350°F, and line two baking sheets with parchment paper. (Or, if you have just one, you can cook in batches).
Wash the kale thoroughly, and remove the leaves from the tougher stems. Tear it into chip-sizes pieces, and place in a bowl.
With your clean hands, lightly massage the oil into the kale leaves – make sure they are coated, but not so much they are dripping.
Pop into the oven for 12 minutes. The kale should darken, and become crispy.
Take it out of the oven, and sprinkle with the salt, red pepper flakes, and grated cheese. Squeeze about half the lemon juice on it.
Return to the oven for another minute or two. Don’t over cook.
Remove from the oven, and squeeze the rest of the lemon juice on the chips while they’re still warm.
Cool, and enjoy.