I hope I'm thinking of the same 'greens' as you all. Kale here (UK) is a bit like a tall floppy cabbage. The best sort is 'curly kale' which looks as if it's had an afro hairdo. But I can't imagine baking it! I usually boil it for three minutes and it's done. Any longer and it goes yellow and all the goodness ends up in the water in the pan. It's one of my favourites, bursting with iron and Vit C, and extra good with a knob of butter.