Preheat oven to 350º.

Place the cranberry sauce, sugar, apple cider & cinnamon in a small saucepan. Cook & stir over low heat on stove until the sugar is dissolved.

Place spiral sliced ham in a baking pan or casserole dish. Spoon about ½ cup cranberry glaze over the ham and place in the oven for 45 minutes.

Remove from oven and glaze again and continue baking until the internal temperature of the ham reaches 140 degrees. (This will take about 10-15 minutes per pound of fully cooked ham.)

Serve any leftover cranberry glaze overtop ham slices.