Baby kale? Hm. I've only ever eaten adult kale. I guess it's like the kale version of veal.
Anyway, I would just blanch it quickly. Or even eat it raw, although I think it's supposed to be one of those veggies that are more nutritious cooked. The thing I love so much about kale is its sturdiness - it'll take being stewed or stuck in a sauce or whatever - but I don't think I'd do that with baby kale which is bound to be more tender. Just a bit of butter and maybe some nice balsamic vinegar.
My family won't eat kale straight up saute'd. I have to put it in a dish. Tonight we are having a chicken sheppards pie with leftover roated chicken, chicken gravy made from chicken stock, onions, carrots, parsnips, celery, and chopped kale...and baby reds and sweetpotatoes for the topper. It's happily cooking in the oven right now.
I love kale in vegetable soups (made with chicken broth).