Adjust oven rack to lower middle position and preheat to 300°F degrees.
Heat a large pot over medium heat, add oil.
Season the meat with salt and pepper and brown it in batches.
Transfer the browned meat to a plate.
After all the meat is browned, combine the meat with the rest of the ingredients in the pot, including the orange rinds.
Bring the mixture to a simmer over medium-high heat, uncovered.
Once it simmers, cover pot and transfer it to the oven.
Cook until the meat falls apart when prodded with a fork, about 3 hours.
Transfer the meat to a sheet pan.
Remove the Bay Leaves & Pasilla.
Degrease the braising liquid by skimming with a large spoon or using a fat separator.
Pour the remaining liquid over the meat.