Warm up spiral-cut ham by covering it with heavy-duty aluminum foil and placing it in an oven set at 325 F. Allow approximately 10 minutes of heating time for each pound of ham. It is also possible to warm smaller portions of ham in a skillet or in a microwave.
Cooked spiral-cut hams that have been handled appropriately are safe to consume cold from the refrigerator. If you wish to eat spiral-cut hams warm, it is preferable to heat only the portion that you intend to consume shortly. Additionally, a meat thermometer can help you adjust the heating time for best results. Retrieve the spiral-cut ham from the oven when the internal temperature of the ham reaches 140 F. For leftover hams or hams that have been repackaged anywhere outside the processing plant, the internal temperature should register at 165 F before you remove it from the oven.
While the United States Department of Agriculture recommends heating spiral-cut ham in an oven preheated to 325 F, some ham companies suggest warming up spiral-cut ham at 275 F for up to 15 minutes per pound of ham. To help retain the juicy texture of the spiral-cut ham, pour some water into a shallow baking pan, and place this pan on the oven rack just underneath the ham. If you are using glaze, brush it onto the ham 10 to 15 minutes before the end of the heating time, and bake the ham, uncovered, until the glaze is hot and bubbly.