Move oven rack to lower third portion of the oven and preheat to 325 degrees F. Line bottom of a roasting pan with aluminum foil for easy cleanup and set aside.
Add orange marmalade, maple syrup, Dijon mustard, bourbon, lemon juice, ground ginger and salt and pepper to a mixing bowls and whisk to combine well. Set aside.
Remove ham from package and pat dry if too wet.
Place ham on roasting rack, flat side down, so the fatty side is facing up.
Gently score the ham in a criss-cross pattern, and brush all over with 1/2 cup of the prepared glaze.
Cover ham loosely with aluminum foil to prevent drying out or burning.
Bake for about 2 - 2 1/2 hours, until instant thermometer inserted into the middle of the ham registers 125-130 degrees F.
Remove roasting pan from the oven and peel back or remove foil from the top and sides of the ham.
Increase oven temperature to 425 degrees F.
Brush 6 Tbsp of glaze over the ham and bake for 20 minutes, brushing ham with additional 6 Tbsp of glaze every 6-7 minutes. You'll be brushing the ham with glaze approximately 3 times during this step.
Be sure to watch that the glaze doesn't burn, but instead turns a rich, deep golden color.
Remove roasting pan from oven and place ham on a large cutting board.
Tent loosely with foil and let ham rest for 20 minutes before slicing.