In a large slow cooker, line the bottom with the slices of white onion.
Layer in the roast.
In a blender combine the cumin, cilantro, pepper, chili powder, lime juice, beef stock, cloves, chipotle peppers in adobo, & garlic cloves. Blend on high for 30 seconds to 1 minute until well combined. Pour over the roast.
Set the slow cooker to low for 8- 10 hours. Or high for 5.
Once done. Shred the meat with two forks, then put the meat BACK IN THE JUICES in the crock pot. Serve with the juices so that it doesn't dry out.
We love to serve this with corn tortillas, cotija cheese (or feta), cilantro leaves, lime wedges, pickled onion, avocado, and sour cream.