Preheat your oven to 160°C (320°F). Place the ham on a baking tray and score the surface in a diamond pattern about 1 cm deep, making sure to cut through the fat but not into the meat.
Combine brown sugar, bourbon, lemon zest, apple cider vinegar, smoked paprika, honey, mustard powder, and soy sauce in a saucepan. Bring the mixture to a gentle boil over medium heat, stirring until the sugar dissolves and the glaze thickens slightly, about 5 minutes.
Brush a generous layer of the glaze all over the scored surface of the ham, making sure to get into the crevices. This initial coat will start to caramelize as it bakes.
Place the ham in the oven and bake uncovered. Every 20 minutes, baste it with more glaze using a basting brush, ensuring each layer is smooth and glossy. The aroma of spices and bourbon will fill your kitchen as it bakes.
Continue basting and baking until the glaze is deeply caramelized and sticky, about 1.5 hours. The ham’s surface should be beautifully glossy and golden brown, with some darker caramelized spots.
Insert a meat probe or an instant-read thermometer into the thickest part of the ham. Once it reaches 60°C (140°F), remove the ham from the oven and let it rest for 15 minutes. This helps the juices redistribute and keeps it tender.
Carve the ham into slices, revealing a juicy, flavorful interior with a beautifully caramelized exterior. Serve warm and enjoy the bright, smoky, sweet notes that make this dish a festive standout.