Light your grill and set up for two-zone cooking, allowing it to preheat to 225 degrees Fahrenheit. Add one chunk of apple wood to the coals to establish clean smoke.

While the grill is preheating, unwrap the ham and evenly coat it with the Dijon mustard and BBQ rub. Then, place it on the grill over indirect heat.

In a saucepan over medium heat, combine the bourbon and brown sugar. Stir until the sugar dissolves and the bourbon starts to cook off slightly, about 2 minutes. Add the cherry preserves, Dijon mustard, orange zest and juice, tart cherry juice, and apple cider vinegar. Stir well and bring to a gentle simmer.

Whisk in the allspice and optional red pepper flakes and let the glaze simmer for about 10–15 minutes, stirring occasionally, until it thickens to a syrupy consistency. Remove from heat and set aside.

When the internal temperature of the ham reaches 145 degrees Fahrenheit as per a meat thermometer (about 90 minutes into cooking) start brushing the glaze generously over the ham. Apply a fresh layer of glaze every 10 minutes until the internal temperature reaches 160 degrees Fahrenheit.

Serve the ham hot with additional glaze if desired.