Preheat the oven to 350ºF.
In a blender, combine the chipotles and adobo sauce, sour cream, ¼ cup of the olive oil, the lime juice, and the salt. Blend until smooth.
Spread one-third to one-half of the chipotle cream sauce over the beef roast and place the roast in a roasting pan or baking dish; reserve the remaining sauce for serving.
In a large bowl, toss the yucca with the remaining 1 tablespoon olive oil and spread out on a sheet pan.
Roast the beef for 2½ to 3 hours, until the beef easily pulls apart with a fork.
When the beef has 45 minutes left in the oven, put the yucca sheet pan into oven and bake. Yucca should be tender when the beef is done.
Remove from the oven and transfer the beef to a cutting board. Let the roast rest for 10 minutes before slicing. Cut the roast in half; shred one half and transfer the meat to an airtight container and refrigerate to use for barbacoa tacos. Cut the remaining half across the grain into ½-inch-thick slices.
Serve the sliced beef with the yucca and the remaining chipotle cream sauce.