1 1/2teaspoonschipotle chile in adobo sauceminced (see notes)
3poundsboneless pork shoulder or butt roasttrimmed
Heat oil in a large skillet over medium-high heat. Add onions and cook. Stir occasionally until they begin to soften, about 3 to 6 minutes.
Add sugar and continue to cook, stirring constantly, until the onions are golden brown, about 6 to 8 minutes more.
Add garlic, oregano, pepper and salt and cook, stirring, for 1 minute. Add vinegar and bring to a boil.
Cook until mostly evaporated, 30 seconds to 1 minute. Remove from the heat and stir in chili sauce and chipotle to taste.
Place pork into a 4-quart (or larger) slow cooker. Pour sauce all over the top. Cover and cook until the pork is almost falling apart, about 3-4 hours on HIGH or 7-8 hours on LOW.
Uncover pork and transfer it to a cutting board. Shred the roast using two forks.
Add pork back to sauce in the crock pot and stir to combine. Cover and keep WARM until ready to serve.
Use tongs to porting pulled pork onto resh rolls for serving. Top with coleslaw mix if desired.
If you like your food spicier, you can add up to 3 teaspoons of chipotle to the sauce. After you use the chipotle chilis in adobo sauce, they will stay good in the refrigerator for up to 2 weeks, or up to 6 months in the freezer.