Combine all ingredients in a slow cooker. Cook on low 8 hours or on high 6 hours. Shred meat. Serve over mashed cauliflower.
Mashed Cauliflower
In a large steamer basket, steam cauliflower until soft. Transfer to a blender. Add a little bit of the cooking water and the butter. Blend until smooth. Sprinkle with salt and pepper to taste.