Place ham, cola, and onion in a large Dutch oven. Bring to a boil. Cover and reduce heat to low. Simmer for 1 hour or until internal temperature reaches 140 degrees F.
To make glaze, stir together honey, dark brown sugar, bourbon, Dijon mustard, cayenne pepper, and black pepper in a small bowl.
Once ham is done simmering, preheat oven to 425 degrees, and discard cooking liquid.
Transfer ham to a roasting pan and make a criss-cross pattern in ham with a sharp knife, going about 1/4-inch deep. Stick a clove in the center of each diamond shape.
Brush the glaze over ham and bake for 20 minutes.