Steve, I freeze a lot of greens. The way I have been doing it is to sautee the washed and chopped kale leaves in a little olive oil and add some salt. The water adhered to the leaves actually helps, so you get a steaming/sautee effect. This is a very light sautee, not for very long, just enough to get the color change in the leaves. After this is cooled down I bag them in ziplock bags and freeze them flat. I also freeze collards, chard and other greens this way. I like the end result after thawing. Usually I cook them a little more upon thawing.

I always blanch first. Not only for better quality, but also for space issues. Kale (esp. curly kale) reduces in bulk a lot when blanched so the freezer space needed is smaller.
I remove the spines, coursley chop the leaves (don't bother to rinse first), drop into boiling water for 3 minutes, strain, and dump into a cold water bath. Then I dry them in a salad spinner and bag them for the freezer. I usually put 12 oz. kale in a gallon size bag and squeeze out as much air as possible.
When thawed, the kale only needs a quick cook. Our favorite way to cook kale is lightly cook 1 tsp of finely shredded ginger and 1 clove of minced garlic in 1 Tbs. oil (don't brown the garlic). Then add 4 Tbs. soy sauce, 2 Tbs. rice wine vinegar, and the thawed kale. Sautee this mixture until kale is heated through and serve. Easy and delicious.

Some people...incl.me leave Kale outside till mid winter or
so, it get's better, less bitter. I have been digging them out
in the snow at minus 25C. Some we just freeze whole.

Konrad

So, Konrad, you freeze your kale too --- right in the garden!
;-]

Thanks for the tip. I often leave leeks out there into the winter, digging them during warm spells (I try to get them all out by Christmas, as the ground isn't likely to freeze solid very far down before then). I don't think they get better but they store better, and don't take up room in my fridge or freezer!

Z

Yes I do...have a bunch still in the garden and haven't had time to get at it. We had minus 10C. already.
We've been told by some former east German folks many years ago
who had us over for dinner [cooked kale with sausage] and from then
on we were hooked! Several freezes will make kale less bitter.
I have to fence them in against deer attacks....

This was in early season..without fence.

Great picture!

Stay warm,

Z