I combine everything except the beef and bay leaves in the blender. I puree until it becomes a vivid red-orange sauce, smooth and thick. This ensures the flavors are well distributed and will permeate every bite of meat.
I trim off excess fat from the chuck roast, but I leave some to help with flavor and juiciness. Then I cut the roast into large, even chunks so that they cook evenly and shred nicely later.
I place the beef in the slow cooker, pour the marinade over, stir so the meat is well coated, and tuck in the bay leaves. Set the cooker to low heat and let it cook for 10-12 hours. If after 10 hours the beef doesn’t shred easily, I cook it another hour. Higher heat sacrifices that melt-in-your-mouth texture.
Once the meat is tender (you can pull it apart with a fork), I shred it lightly. Then I switch the cooker to warm and let the shredded meat sit for 15-20 minutes so it soaks up juices. Sometimes, I spread it on a sheet pan and broil it for 5-8 minutes to get crispy bits — optional, but totally worth it.