Spray the slow cooker with cooking spray. Place the semi-boneless smoked half ham flat side down in a 6-quart slow cooker.
In a separate bowl, mix together the brown sugar, cinnamon, and ground clove. Pat the mixture on top of the ham until you’ve used it all. Then pour 8 ounces of maple syrup on top. Place the lid on the slow cooker and cook on high for 4 hours or low for 8 hours.
Carefully remove the ham from the slow cooker, slice, and serve. Pour sauce from slow cooker in a bowl to be ladled on top of ham if desired.
Have leftovers? Freeze in freezer bags for up to 3 months. When you're ready to have the ham, just thaw it and enjoy!