When you buy a ham from the grocery store, more often than not, it is already fully cooked or smoked. This means your primary job isn’t actually “cooking” in the traditional raw-to-done sense, but rather reheating it so that it remains juicy, flavorful, and tender. Learning how to cook a cooked ham in the oven is a fundamental skill for holiday hosting, Sunday dinners, or meal prepping for the week. If done incorrectly, you end up with a dry, salty brick; done right, you get succulent slices with a caramelized glaze that guests will rave about.
Understanding Your Ham Options
Before you preheat your oven, it is essential to know exactly what kind of ham you have sitting in your refrigerator. Not all “cooked” hams are created equal, and the cut will dictate your timing and technique.
Most hams sold in supermarkets are “city hams.” These are wet-cured, usually smoked, and fully cooked. They are sold either whole, half (shank or butt end), or spiral-sliced. A spiral-sliced ham is incredibly convenient because the bone-in meat has already been cut in a continuous circle, making serving a breeze. However, because the meat is already sliced, it is much more prone to drying out in the oven.
A “country ham” is a different beast entirely. These are dry-cured, aged, and very salty. They often require soaking for 24 hours before they even touch an oven. For the purposes of this guide, we are focusing on the standard, fully cooked city ham that most families serve at Easter, Thanksgiving, or Christmas.
Essential Tools for Success
To achieve the best results, you don’t need a kitchen full of gadgets, but a few key items are non-negotiable. First, you need a sturdy roasting pan. If you don’t have one, a large 13×9-inch baking dish can work for smaller hams, but a roasting pan with a rack is ideal because it allows heat to circulate under the meat.
Second, and perhaps most importantly, you need a meat thermometer. Since the ham is already cooked, your goal is to reach a specific internal temperature without overshooting it. Relying on time alone is risky because oven calibrations and ham shapes vary. Finally, you will need heavy-duty aluminum foil. This is your primary defense against moisture loss.
Preparing the Ham for the Oven
Start by taking your ham out of the refrigerator about 1 to 2 hours before you plan to cook it. Bringing the meat closer to room temperature ensures more even heating. If you put a direct-from-the-fridge, ice-cold ham into a hot oven, the outside will dry out before the center is warm.
Remove all packaging, including the plastic disc that often covers the bone. Give the ham a quick rinse under cold water to remove any excess salty brine from the surface, then pat it dry with paper towels.
If you are using a whole or half ham that isn’t spiral-sliced, you may want to score the fat. Use a sharp knife to cut a diamond pattern into the fat layer, being careful not to cut deep into the meat itself. Scoring not only looks beautiful but also provides channels for your glaze to seep into the meat.
The Roasting Process
The secret to a juicy ham is “low and slow.” You aren’t looking to sear the meat; you are looking to gently bring it up to temperature. Preheat your oven to 325 degrees Fahrenheit. This moderate temperature is the sweet spot for reheating without toughening the proteins.
Place the ham in your roasting pan. If it is a half ham, place it flat-side down. This protects the most vulnerable part of the meat from direct heat. Add about a half-inch of liquid to the bottom of the pan. Plain water works, but you can add flavor by using apple cider, pineapple juice, or even a splash of ginger ale. This liquid creates a steamy environment inside the foil tent.
Cover the pan tightly with heavy-duty aluminum foil. Ensure there are no gaps where steam can escape. This is the most critical step in preventing a dry ham.
Timing and Temperatures
As a general rule of thumb, a fully cooked ham needs about 10 to 14 minutes per pound to reach the desired internal temperature. For a standard 8-to-10-pound ham, this usually takes between 2 and 2.5 hours.
Your target internal temperature is 140 degrees Fahrenheit. This is the temperature at which the ham is hot enough to be delicious but hasn’t yet begun to lose its structural moisture. Start checking the temperature with your meat thermometer about 30 minutes before the estimated finish time. Insert the probe into the thickest part of the meat, making sure not to touch the bone, which can give a false high reading.
The Art of Glazing
While a ham is tasty on its own, a glaze is what turns it into a centerpiece. Most glazes involve a balance of sugar (brown sugar, honey, or maple syrup) and acid (mustard, vinegar, or citrus juice), often spiked with spices like cloves, cinnamon, or ginger.
The mistake many people make is putting the glaze on too early. Because glazes have high sugar content, they will burn if they are in the oven for the full duration of the cooking time. The best time to glaze is during the last 20 to 30 minutes of heating.
Once the ham reaches about 130 degrees Fahrenheit, remove it from the oven and turn the heat up to 400 degrees Fahrenheit. Carefully remove the foil. Brush a generous layer of glaze over the entire surface, ensuring it gets into the scores or between the spiral slices. Return the ham to the oven uncovered. Repeat the glazing process every 10 minutes until the ham reaches 140 degrees Fahrenheit and the glaze is bubbly and caramelized.
Resting Before Serving
The final step is often the hardest because the kitchen smells incredible, but you must let the meat rest. Once you pull the ham out of the oven, transfer it to a cutting board and tent it loosely with foil. Let it sit for at least 15 to 20 minutes.
During this time, the juices inside the ham redistribute. If you cut into it immediately, the moisture will run out onto the board, leaving the meat dry. Resting ensures that every slice remains succulent.
Tips for Spiral Sliced Hams
If you are cooking a spiral-sliced ham, you need to be even more cautious. Because the surface area is much larger due to the slices, moisture evaporates quickly. Many experts recommend wrapping the ham itself tightly in foil before putting it in the pan, or even cooking it cut-side down in a shallow pool of liquid to “steam” the slices back to life. Keep the temperature strictly at 325 degrees Fahrenheit and check the internal temp frequently, as they tend to heat faster than solid hams.
Repurposing Leftovers
One of the best parts of cooking a large ham is the leftovers. Beyond the standard sandwich, diced ham is a fantastic addition to omelets, quiches, and split pea soup. The ham bone itself is a treasure; don’t throw it away. Simmer it with beans or in a stockpot to create a smoky, rich base for soups and stews. You can freeze the bone for up to three months if you aren’t ready to use it immediately.
Frequently Asked Questions
- How long do I cook a pre-cooked ham per pound?
For a fully cooked ham, you should plan for 10 to 14 minutes per pound when roasting at 325 degrees Fahrenheit. The exact time will vary based on whether the ham is bone-in or boneless and its overall shape. Always use a meat thermometer to ensure it reaches an internal temperature of 140 degrees Fahrenheit. - Should I add water to the bottom of the roasting pan?
Yes, adding about a half-inch of liquid (water, juice, or cider) to the bottom of the pan is highly recommended. This creates steam under the foil cover, which helps keep the ham moist during the long reheating process. - Do I need to cook a “fully cooked” ham?
Technically, you can eat a fully cooked ham straight out of the package, but it is much more palatable when heated. Reheating allows the fats to soften and the flavors to develop. If you are serving it for a meal, heating it to 140 degrees Fahrenheit provides the best texture and flavor experience. - How do I prevent a spiral-sliced ham from drying out?
To prevent a spiral ham from drying out, wrap it very tightly in heavy-duty aluminum foil to trap all moisture. You can also place it cut-side down in the pan and add liquid to the bottom. Avoid overcooking; start checking the temperature early, as sliced meat heats through faster than a whole roast. - Can I glaze a ham without an oven?
While the oven is the best place to caramelize a glaze, you can use a kitchen torch for a similar effect on a smaller scale, or you can simmer your glaze on the stovetop until it is thick and syrupy, then pour it over the warm ham just before serving. However, for that classic “baked-on” crust, the oven’s high heat at the end of the process is the most effective method.