Mix together the brown sugar, apricot jam and mustard powder in a small bowl. Brush onto the ham using a pastry or barbeque brush. Reserve any leftover glaze.
Enclose the foil around the ham and place on a rimmed baking sheet. Roast for 2 hours in preheated oven. Apply the remaining glaze 20 minutes before the ham is done.
NOTE: If your ham is a different side figure 12 minutes per pound.