This one is for a party. The Latin dessert sauce, dulce de leche, made by boiling milk til it's caramel like, is used here to create a sweet and tangy glaze for your holiday ham. This is a true crowd pleaser. The final sugary and salty flavor, after the long roasting process, is out of this world. Be sure to save the ham bone for soup.
In small bowl, whisk the dulce de leche together with the two mustards, the garlic and the cayenne. Whisk in 1/4 cup of the chicken broth.
Trim the skin off the ham, leaving a 1/4 inch thick layer of fat. Score the fat, about 1/8 inch thick, in a diamond pattern. Spread the onion slices on the bottom of a large roasting pan. Set the ham on top and add 1/2 cup of the chicken broth to the pan. Cover the roasting pan with foil and roast the ham for 1 hour
Remove foil and b rush ham with all but 1/4 cup of the dulce de leche glaze. Roast ham for 1 hour longer or til nicely glazed all over, the internal temperature should be 140 degrees. Transfer ham to cutting board and let the ham rest for 15 minutes
Pour pan drippings into a small pan and skim off as much of the fat as you can. Set roastig pan on top of stove over medium heat, preferably over two burners. Add remaining 1/2 cup of chicken broth and cook, scraping up any browned bits from the bottom and sides of the pan. pour deglazed liquid into the pan with the pan drippings. Whisk in the remaining 1/4 cup of dulce de leche glaze and bring mixture to a boil. Slice the ham and serve with the glaze.