Make Spice Rub

1. Grind cumin seeds, coriander seeds and black peppercorns until in a coarse powder. Mix together with the other spices for the spice rub

Marinate Ham

1. Mix together citrus juices in a small bowl
2. Make a few diagonal slits with a sharp paring knife in the fat of the ham (but do cut through to the meat)
3. Coat ham with Worcestershire sauce, then with citrus juices making sure to get into all of the slits in the meat
4. Rub minced garlic all over the ham as well as the dried spices and chopped cilantro
5. Place on a roasting pan, cover with plastic and refrigerate at least 8 hours to overnight
6. Pull ham out of refrigerator 1 hour prior to cooking
7. Preheat oven to 475º
8. Roast ham for 30 minutes, then drop the oven temperature down to 375º. Roast an additional 18-20 minutes per pound, or until the internal temperature reads 150º

Make Glaze

1. Meanwhile, during the last hour of cooking, prepare the glaze. Add all glaze ingredients to a medium sauce pan, cover and bring to a simmer over medium heat , or until the piloncillo is melted
2. Remove lid and reduce liquid until it reaches a syrupy consistency, about 10 minutes over medium-low heat
3. Baste the ham with the glaze, and continue to baste/glaze every 10 minutes until the end of cooking
4. When the internal temperature reaches 150º, remove from oven and allow to sit one hour before slicing and serving