Place the wrapped ham, still in the original packaging, in a large container and fill it to the top with hot tap water. Let is stand for 45 minutes. Drain off the water. Fill it up with hot tap water again and let it stand for another 45 minutes.

Preheat the oven to 250 degrees.

When the ham has warmed through, place it in a large roasting pan, or a glass casserole dish (if it's large enough) inside a large oven bag. Close the bag tightly around the ham and cut off the extra plastic at the top. Poke some holes in the top of the bag, 3-5 holes, to prevent the bag from exploding.

Meanwhile, combine all the ingredients for the glaze in a small saucepan. Bring it to a boil and set aside.

Bake the ham in the oven for 1-1 ½ hours, approximately 10 minutes per pound, until the ham reaches 100 degrees on an instant read thermometer.

Increase the heat to 350 degrees.

Cut open the oven bag and roll it down around the bottom of the ham. Brush the glaze over the ham. If the glaze has become cold and thick, reheat it on the stove again.

Bake the ham for another 15 minutes, with the glaze on.

Take it out of the oven and let it rest for about 15 minutes before serving.

Add 4-6 Tablespoons of ham juices with the remaining glaze and cook on high heat, until the glaze thickens, about 5 minutes. Serve with the ham.