Preheat your oven to 300°F.
Then, peel and quarter the onion, and place it at the bottom of a large Dutch oven.
Generously season the pork shoulder with salt and pepper on all sides.
Place the seasoned pork on top of the onions in the Dutch oven.
Pour the can of chipotle peppers over the pork, ensuring the sauce covers the meat evenly.
Next, pour both cans of Dr Pepper into the pot.
Add the brown sugar to the mixture in the pot, stirring gently to combine with the liquid.
Cover the Dutch oven with its lid.
Place the pot in your preheated oven and cook for about 6 hours or until the pork is tender enough to be easily shredded.
You can enjoy it in various styles!