Directions :

1. Remove the ham from the packaging, including the plastic disk covering the bone. Place the ham in an oven bag, then twist and tie the bag shut. Trim excess oven bag. Place the ham cut-side down in a 9-inch by 13-inch baking dish. Allow the ham to sit at room temperature for 90 minutes.
2. Arrange an oven rack in the lower-middle position and preheat the oven to 325 degrees. Bake the ham until the center registers 140 degrees, about 1 ½ to 2 ½ hours (approximately 15 minutes per pound). (Open slightly or lift bag to take temperature; do not puncture.)
3. Meanwhile, in a medium saucepan, mix the brown sugar, cornstarch, and salt together. Stir in crushed pineapple with syrup, lemon juice, and mustard. Bring to a boil over medium-high heat Boil until glaze thickens, about 1 minute, stirring constantly.
4. Remove the ham from the oven and roll back the sides of the oven bag to expose the ham. Brush the ham with about half of the glaze. Return the ham to the oven and bake 10 minutes longer, or until the glaze is sticky and ham reaches 145 degrees on a digital thermometer.
5. Remove the ham from the oven. Remove the oven bag and return ham to baking dish. Tent loosely with foil. Allow the ham to rest for 20 to 30 minutes. Serve with remaining glaze.