Sadly, Jamie's people have made it all but impossible for me to cut and paste the recipe here, so you'll just have to visit his site. It's worth it for the picture anyway.
A few notes on the recipe: If you are a slow-cooker type, you can absolutely dump the whole deal into the cooker and set it on low for 8 hours. Works just as well as the oven. Also, as Jet pointed out, when you cook chiles for ages, they lose most of their heat, so you can easily double the number of chiles and still have the results be fairly mild. If your pork is exceptionally cubic, you may want to cut it in half so as to reduce the amount of liquid needed to cover the pork. And finally, do not skip the part where he tells you to add lemon zest to the sour cream. It is a critical flavor element at the end, and I promise you will LOVE it.
We made it for some of my husband's coworkers to absolute raves. It's hard to go too far wrong with pork shoulder, but this is truly excellent.