Preheat oven to 325°F.
Unwrap the ham and place it in a large baking dish. I also decided to pour all the juices from the bag in the dish, to help keep it juicy.
If you have a spiral-cut ham, there’s nothing else to do. Otherwise, make ¼″ deep cuts in a diamond pattern all over the ham surface (this will allow the juices from the brown sugar ham glaze to drip down inside later).
Place in the oven and bake.
A ham will take about 1 to 1-½ hours to cook through. After 1 hour, check the temperature by inserting a meat thermometer in the thickest part (being careful not to touch the bone). The ham is ready when the internal temperature has reached 130°F.
At about the 1-hour mark, start making the brown sugar ham glaze.
Melt butter in a small pan over medium heat.
Once the butter has melted, add all the other ingredients and whisk together.
Bring to a simmer, whisking occasionally, and cook for about 5 minutes.
Immediately remove from heat and let cool for 5 to 10 minutes.
Check the internal temperature of your ham (the ham is finished cooking when it has reached 130°F).
When it’s getting close to that point, but has about a half hour left, baste half of the brown sugar ham glaze onto the ham.
Fifteen minutes later, brush on the remaining ham glaze and let the ham finish cooking until it has reached 130°F.
Serve and enjoy!