Preheat the oven to 200ºC. Mix all the ingredients for the glaze in a bowl. Score the ham in a criss-cross pattern. Massage the glaze on top, reserving ¼ for later.
Place the glazed ham in an oven dish lined with baking paper and bake for 40-45mins, or until the top is caramelized. Spoon over the remaining glaze and allow to sit at room temperature for 15mins before carving.