1. Preheat oven as directed on the ham package. Follow the packaging instructions for baking the ham, removing the ham from the oven when internal temperature reaches 150°F, about 30 minutes before the end of recommended heating time.
2. In a small bowl, combine the brown sugar, mustard and 2 tablespoons of the reserved pineapple juice to make a thick glaze.
3. Brush ham with the glaze and arrange the pineapple slices on top of the ham, securing them with cloves or toothpicks. Then, place a cherry in the center of each pineapple ring and secure with a clove or toothpick. Continue to bake for another 15 minutes.
4. Remove ham from the oven, transfer to a cutting board and carve.