1. Let ham rest at room temperature for 30 minutes. Meanwhile, preheat oven to 300 degrees.
2. Score the ham to form a diamond pattern by making shallow cuts through the fat on the diagonal. Place the ham, flat-side down, on a rack in a roasting pan. Pour 1/4 inch of water into the bottom of the pan. Roast the ham until it reaches an internal temperature of about 130 degrees(between 2 and 2 1/2 hours).
3. Meanwhile, combine the brown sugar, honey, olive oil and onion powder in a small saucepan. Heat over low until warmed and combined.
4. Combine the breadcrumbs, mustard and coriander in a small bowl.
5. Remove the roasted ham from the oven and turn the heat up to 400. Brush the honey mixture all over the outside of the ham. Carefully pat the bread crumb mixture onto the ham.
6. Return to oven and roast for 10 to 15 minutes, until the crumb coating is golden brown.