Preheat oven to 300°F or smoker to 275-300°F. Place ham cut-side down in a roasting pan lined with foil. Cover tightly with foil. If smoking, use apple, cherry, or pecan wood.
Combine all glaze ingredients in a medium saucepan over medium heat. Simmer for 6-8 minutes until slightly thickened and coating the back of a spoon. Remove from heat and reserve 1 cup for serving.
Cook covered ham for 1.5-2 hours in oven or 2-2.5 hours in smoker until internal temperature reaches 120-125°F.
Remove foil. Brush ham generously with glaze, making sure it runs between spiral cuts.
Continue cooking uncovered. Brush with glaze every 15-20 minutes for 45-60 minutes total until internal temperature reaches 135-140°F. The exterior should be sticky, glossy, and caramelized.
Rest ham for 10-15 minutes. Warm reserved glaze and serve alongside sliced ham.
Notes
Use pure maple syrup for best flavor. The bourbon cooks out completely, leaving vanilla and oak notes. Multiple glaze layers create the lacquered finish. Don't skip the orange zest - it brightens the richness. Leftover ham is perfect for sandwiches, omelets, and soups.