Preheat the oven to 325 degrees F (165 degrees C).
Prepare ham: Add water, star anise, and cloves to the bottom of a roasting pan. Place a roasting rack into the pan; place ham on the rack. Cut 1/4-inch-deep slashes, 1/2-inch apart, lengthwise and crosswise across the top of ham.
Bake in the preheated oven for 20 minutes.
While ham is baking, make glaze: Whisk together brown sugar, honey, mustard, vinegar, black pepper, Worcestershire sauce, and cayenne pepper in a medium bowl until thick and smooth.
Brush glaze all over ham. Continue baking ham, brushing with glaze every 20 minutes, until glaze is deep golden and ham is heated through, about 2 hours 10 minutes. An instant-read thermometer inserted into the center of ham should read at least 145 degrees F (63 degrees C).
Run a kitchen torch over ham until glaze is crispy and caramelized, 2 to 5 minutes.