To make the cranberry gastrique:
Sprinkle the sugar over the bottom of a heavy large frying pan over medium heat. Cook without stirring for about 9 minutes, or until the sugar melts and then turns a deep golden brown color. As the sugar browns, tilt the frying pan to distribute the melted sugar, but do not stir.
Gradually add the vinegar (the mixture will harden). Stir until the caramel begins to melt, about 1 minute. Add the ginger, cinnamon, star anise, and 1 rosemary sprig and stir for about 2 minutes, or until the caramel is mostly melted. Add the cranberries and 1/3 cup of water and cook for about 10 minutes, or until the cranberries are tender and release their juices. Strain the mixture through a fine meshed sieve; discard the solids.
Meanwhile, to prepare the ham:
Position the oven rack on the bottom rung of the oven and preheat the oven to 350°F.
Place the remaining 2 rosemary sprigs in the base of the roasting pan. Set a roasting rack in the pan. Remove the skin from the ham, leaving the fat intact. Run a small dull knife over the fat to lightly score it all over. Place the ham on the rack in the roasting pan, cover, and bake for about 1 hour and 10 minutes, or until a meat thermometer inserted into the thickest part of the ham registers 200°F.
Brush the ham with some of the liquid from the cranberry gastrique. Continue to bake, uncovered, for another 25 minutes, brushing the ham with the cranberry gastrique every 10 minutes. The gastrique should form a glaze over the ham and the ham should register at least 250°F on the thermometer. Transfer the ham to a carving board and let it rest for 10 minutes.
Transfer the remaining cranberry gastrique to a small serving bowl. Carve the ham and arrange the slices on a platter. Serve hot or warm with the cranberry gastrique.
Recipe Copyright Chef Curtis Stone, 2017