Prepare the glaze. In a bowl, using a fork, mix together the orange marmalade, Dijon mustard and butter.
You may want to make an additional batch of the glaze and serve it as a spread!
Remove the ham from oven and spread the glaze over the entire surface of the ham and return to the oven for 30 minutes.
The ham should cook for a total of 4 hours or until an internal temperature of 140˚F is reached.