How to Make It
Roast the poblanos directly over a gas flame or under a preheated broiler, turning, until charred all over. Let cool. Peel, seed and stem the chiles, then slice them into 1/4-inch strips.
In a large, deep skillet, melt the butter in the oil. Season the pork chops with salt and pepper and dredge them in flour. Add the chops to the skillet and cook over moderately high heat, turning once, until golden brown, about 7 minutes. Transfer to a plate.
Add the onion, garlic and a generous pinch each of salt and pepper to the skillet and cook over moderate heat, stirring occasionally, until very tender and caramelized, about 8 minutes. Add the poblanos and the 1 tablespoon of flour and cook over moderate heat, stirring, until the flour is lightly golden, about 3 minutes. Add the chicken stock and bring to a simmer, scraping up any browned bits from the bottom of the pan.
Return the chops to the skillet and simmer over a moderately low heat, turning once, until cooked through, 7 to 10 minutes. Transfer the chops to a platter. Stir the crème fraîche into the gravy and season with salt and pepper. Spoon the poblano gravy over the chops and serve with steamed rice.