Heat vegetable oil in a large skillet over medium high heat.
Season roast with 1/2 teaspoon salt and 1/4 teaspoon pepper.
Add roast to skillet to brown and sear all sides, about 4-5 minutes per side.
While roast is cooking in a food processor add chipotle peppers, adobo sauce, lime juice, garlic cloves, vinegar, cumin, oregano, cloves, 1/2 teaspoon salt, 1/4 teaspoon pepper and blend until smooth.
With machine still running stream in beef broth until combined.
Add beef to slow cooker and pour marinade on top.
Add bay leaves then cover and cook on low for 8-9 hours or on high for 4-5 hours until meat is tender.
Remove meat from slow cooker and place on cutting board.
Once cool to touch shred beef using two forks.
Stir shredded beef back in slow cooker with sauce and continue to cook for 15-30 minutes.
Remove bay leaves then serve as desired.
Notes
For less heat start by adding only 1/2 tablespoon adobo sauce and 2 chipotle peppers. You can always add more if needed. I make it with 1 tablespoon adobo sauce and 3 chipotle peppers.