Preheat the oven to 350˚F. Slice the ham and put it into a Dutch oven or a casserole dish with a lid. *see below for slow cooker instructions
To make the ham glaze, mix together brown sugar, ground mustard, orange juice, and honey in a saucepan. Bring to a boil over medium heat, stirring often.
Pour the glaze over the ham. Put the cover on the Dutch oven or casserole dish and place it in the oven. Bake at 350˚F for about one hour or until it reaches an internal temperature of 140˚F, basting after 30 minutes.
Notes
Crockpot Instructions:Place the sliced ham in the crockpot and pour the glaze over it. Cover and cook on low for 3-4 hours, or until it reaches an internal temperature of 140˚F, basting occasionally.