The safest: Thawing in refrigerator (when you have time). Allow about a day for every four to five pounds of meat. So, plan on at least three days for 12-lb ham.
Advantage: Meat remains cold enough to stop bacterial growth. Advantage: Flexibility if plans change. A thawed ham can safely stay in the fridge for a few additional days. Saving a few hours doesn’t compare more then this safety buffer.
How to Thaw Ham Safely
It cuts process down about seventy percent, but it need watching. Plunge into cold tap water with seal still on and you’ll shave about seventy percent off that time. Because the water warms up and can pose a risk for bacterial growth, change it every half hour to keep the thawing process efficient. Swapping the water keeps conduction efficient and surface temperature safe. Do not ever use hot or warm water. Using warm water will cook outside of your ham while leaving interior frozen. This create a danger zone for pathogens.
If you are in a pinch, microwave is your friend when you need something in a hurry. But heating is uneven, leaving some parts frozen and others hot even though it is fast. If you use the microwave to defrost it, the ham should of go straight into oven to be cooked. Don’t leave it sitting around while it cools, it’ll start growing bad stuff. So there is no room for error if you do this.
There’s never a free lunch here; you pay a safety price for speed. Can’t have both speedy defrost plus casual scheduling. Respect the clock: manage your expectations by using the microwave only when you’re desperate, water bath if you have hours, or fridge if you have days.
Ham need to be kept cold… Don’t leave it out on counter, as room temp encourages bacteria growth. Place ham on bottom shelf of fridge so it can catch any drips without contaminating other foods. Let the meat stay cold until it go into the oven. Trust the slow way, plan ahead, and enjoy a tender and safe meal.