What you need:
Kale (I'm using fancy kale here, which I find works best, but any will work)
Cheese (I use grated parmesan or grated blends)
Spices to taste (I use chili powder, cayenne (red) pepper, cumin, paprika, and black pepper)
Large mixing bowl(s)
Step 1: Prepare the Kale
Wash your kale under warm running water and shake as much of the water off of them as you can.
Kale leaves have a very tough rib running up the center of them, which we're going to discard. I'm sure there's a use for them, but I've not experimented with that.
Tear the kale leaves into bite-size pieces while removing them from the ribs. If you've purchased pre-cut kale (eg, from Trader Joe's) then all you need to do is wash the kale. Yes, even if the packaging says pre-washed.
The kale I use is lobed, and I find the lobes are generally bite sized, or two-bite sized which is fine.
Put the clean leaves into the mixing bowls... on to step 2.
Step 2: Oil the Kale
I like using fancy kale for that reason -- those nooks and crannies do a great job holding in all of the flavorings I'm about to add.
Wash your hands to get the oil off of them.
Now is a good time to turn on the oven and preheat to 325ºF.
Step 3: Cheese the Kale
Yes, you can use fresh-grated parmesan, romano, mozzarella, blends, whatever you like. The grated shakey-cheese is easiest for me, and tastes just fine.
Blend the cheese in by hand the same as you did with the oil. Turn the leaves over in the bowl, mix thoroughly, get the cheese gratings into all the folds and frills of the leaves. If done right, none of the cheese will remain in the bottom of the bowl and all of it will be stuck to the kale.
Wash your hands, and move along to the next step....
Step 4: Season the Kale
I use a liberal amount of chili powder, an almost as liberal amount of cayenne pepper (often sold as red pepper), some cumin and paprika, and a (relatively) small amount of black pepper.
By now, you know the drill... start mixing it all together by hand. It's really worth spending the time here to mix and rub the spices through all the leaves, even if they look well-blended. The last thing you want is a clump of chili powder hidden in some frills on a kale chip giving you an overpowering dose of heat while you're snacking.
Wash your hands.
I cannot stress this enough.
WASH YOUR HANDS.
Before you do anything like lick your fingers, rub your eyes, or scratch an itch, (or worse, rub someone else's eyes or scratch one of their itches) wash your hands. Seriously, do NOT rub your eyes while mixing this stuff. You will regret it.
Your fingers are coated with a concentrated mix of capsaicin-rich spices until you wash them. It's your call, I take no responsibility for your actions now that you're fairly warned.
Step 5: Bake the Kale!
Once your paper is in place, lay the seasoned, cheesed kale on the parchment paper in a single layer, trying as best as you can to spread the leaves out and not pile them up. They can be close and/or touching, but must be in a single layer. For the batch I made, I needed four baking sheets to bake the whole batch.
If your oven is preheated, then place the baking sheets in the oven and set a time for 10-12 minutes. They will probably not be done in that time, but you don't want to overdo them.
Move on to the next step after washing your hands, which will discuss how to tell when the chips are done.
The edges of the kale leaves are dry and crisp, not oily and soggy.
The leaves' centers are not wet, and not still a bright, chlorophyll green.
Deciding when to take the baking sheets out of the oven takes practice and also involves a bit of personal preference.
If you push at the edge of kale chip and it doesn't just slide as a single piece, if it squishes in on the place you pushed but doesn't move because the center is still wet and oily (and thus still sticking to the parchment paper) they need more time.
With each check, if I decide they need to cook some more, I set a new timer for 3 minutes, and continue to re-check in 3-minute intervals. Because we're using a low temperature to bake them, it's unlikely they will burn but they can become over-brittle. We don't want to dehydrate them, we just want to crisp them up. All told, mine took about 20 minutes to cook.
Kale chips that are done will be mostly dark-green to olive in color, crispy but not brittle throughout, and will act like chips when pushed around the baking sheet or picked up - they'll be stiff and crisp, not bendy or wilted.
SOME of the leaves may still be a bit underdone when you pull the pans from the oven, that's OK. They'll dry up a bit while they cool, and even if they don't, it's not a huge deal if some of the chips aren't perfectly crispy. They'll still taste fine.
In researching this recipe originally, there was some disagreement on the right temperature and time to cook these for. Feel free to experiment with higher temperatures for shorter timeframes, but I find the numbers I use are fine. A slow bake at lower temperatures means less risk of frying the chips in their own oil and much lower risk of burning them. We want to bake the chips; the oil serves to carry the flavorings and preserve the moisture so the chips are crispy but not fragile.
While the chips are out cooling, be sure to set up proper perimeter defenses against hungry roommates or family members, as you can see I did not.
To serve the kale crisps, clean one of your mixing bowls (or get out another bowl), and carefully pick up a parchment paper. The kale chips should stick to them slightly, enough to tip one end of the paper into the bowl. Give the paper a shake and a few taps, and the chips will either slide or fall right off the parchment and into the bowl. Give your cookie sheets a wipe down in the chance some spiced oils leaked around or through the parchment, put away your ingredients, and enjoy your new wintertime (or anytime) snack!