Trim rind and excess fat from the ham, leaving a 1/4-inch thick layer of fat. With a sharp knife, score the fat in a diamond pattern. Place the ham in large roasting pan and sprinkle with the allspice. Pour the cola into the pan and bake uncovered 1 hour and 15 minutes, basting every 15 minutes with the pan juices.

Meanwhile, in a medium saucepan, combine the cherry preserves, orange juice, and liqueur over medium heat and cook, stirring, until melted, 1 to 2 minutes.

Remove the ham from the oven and brush the top and sides with the cherry glaze. Return the ham to the oven and bake, brushing with pan juices and glaze every 15 minutes and tenting the ham with foil if browning too quickly, until an instant-read thermometer inserted into the thickest part of ham without touching the bone registers 140 degrees F, about 15 to 30 minutes.

Remove the ham from oven and let rest for 30 minutes to 1 hour before slicing. Serve warm or at room temperature, thinly sliced, with biscuits or dinner rolls and mustard to make sandwiches.