In case I can't find fresh poblanos, what types of chiles would be a good substitute?
Hi Jess -- I've only made the recipe using poblano, but I think serrano would be a good substitute. Let me know how it turns out!
I would try roasting a green pepper and then adding some heat in another way - cayenne or red pepper flakes.
To my knowledge, a fresh poblano is an ancho. A dried ancho is a poblano.
A poblano is a thick fleshed fresh green pepper in a triangular shape that is roughly the size of a green bell pepper. It is often mistakenly labedel in stores as an pasilla pepper (a dried pepper). It has a light heat, but that heat varies a bit and they are occasionally hotter than expected. I would use equal volume of green or red bell peppers plus a jalapeno or serrano to add a bit or heat (or use cayenne, flakes, like suggested above.) Or even better would be anaheim peppers with the hot peppers added, seeded or not.
An Ancho is a dried Poblano, so if you see a fresh ancho, it is the triangular poblano that you want. But usually they will call them Pasilla which are the really dried type of another chile.
The Cooks Theasarus makes it very clear (and is accurate):