Serves 15 to 20
1 bone-in smoked ham (10 pounds)
1/4 cup whole grain mustard
2 tablespoons apple cider vinegar
1/2 cup apricot preserves
Preheat oven to 325 degrees. Wrap ham completely with parchment paper-lined aluminum foil and place on a rimmed baking sheet or roasting pan. Transfer ham to oven and bake for 1 hour. Place apricot preserves in a 1-quart saucepan and bring to a simmer over medium-high heat. Transfer preserves to a blender and puree until smooth, about 2 minutes. Strain through a fine mesh sieve set over a small bowl; discard solids. You should have slightly less than 1/2 cup remaining. Add mustard and vinegar to bowl of preserves; stir to combine.
Unwrap ham; discard parchment and foil. Transfer ham to a cutting board. Using a large sharp knife, score fat in a diamond pattern, making the lines about 3/4 inch apart. Return ham to roasting pan.
Increase oven temperature to 375 degrees. Brush ham evenly with 3/4 of the preserve mixture and return to oven. Bake ham for 30 minutes. Brush ham with remaining glaze and continue cooking 10 minutes more. Transfer to a cutting board until ready to carve.