Use a blender or food processor, add puree ingredients, & process on high speed until smooth; set aside.
Slow Cooker Directions:
Sear the beef in a large skillet & then transfer to your slow cooker.
Add the puree to the beef & add the bay leaves, stir to combine, close lid, and cook for about 4 to 5 hours on High or about 7 to 8 hours on Low.
When done, discard bay leaves, shred the meat with 2 forks, and allow it to sit in the juices for about 15 minutes before serving so it soaks up even more flavor.