Heat oven to 325 degrees. Line a roasting pan or oven proof dish with foil. Take ham out out packaging and place in pan, cut side down. Wrap with foil and securing tightly so that no steam is releases. Place in oven and bake for 2 hours.
In a non-stick pot, combine frozen orange juice concentrate, ground ginger and molasses. Stir together. Cook on low, watching carefully so that it does not boil over, until glaze is reduced by 1/3 - about 15 minutes.
When 2 hours cooking time is done, unwrap and pour 1/2 of glaze over ham. Place back in oven for 10 minutes. After 10 minutes, pour over remaining glaze and cook for last 10 minutes. Remove from oven, let rest 15 minutes, the slice and serve.