I've had this twice in the past 2 weeks at a Mexican place outside Reading called Alebrije.
It's a seasonal dish used to celebrae Mexican Independence day, which I believe is September 15. It's spicy, sweet, savory, creamy. Possibly one of the most delicious creations I've ever had.
A roasted poblano is stuffed with a delicious mixture of beef/pork, raisins, almonds, apples, peaches, pears, and acitron. The warm, stuffed pepper is topped with a cold walnut sauce - creamy but not heavy.
Apparently, it's quite labor intensive, especially if you use fresh ingredients.
Anyone familiar with Chiles en Nogada? Where else are they serving it?