I have a question about the ingredient "cavolo nero - young tender leaves" on the recipe "Zuppa Frantoiana - Olive Harvest Day Soup" from Maria Teresa Jorge.
Cavolo nero is also know as dinosaur kale, black kale, or lacinato kale. It can be found in upscale grocery stores or farmer's markets.
Per hardlikearmour's answer it is actually getting much easier to find. Whole Foods of course, but now I'm even seeing it in supermarkets. Commercially it's being grown in California.