Pasilla/Poblano: Juan said these are interchangeable. There is apparently some debate on this. But for purposes of fresh, I suppose if you see either in the store, you can probably use them in similar preparations. They are usually mild, but Juan notes they can sometimes be spicy. (Wikipedia notes: "Different peppers from the same plant have been reported to vary substantially in heat intensity.") Juan uses them for chile rellenos. He said the skin is hard, need to roast the pepper over flame and remove it. Here are some Rick Bayless ideas for chile rellenos. Juan also likes to make a sopa poblano with jalapenos, passilla, zucchini, mushrooms, potatoes - all roasted and blended - and sour cream.