Whisk first measure of Chelsea Soft Brown Sugar, orange juice and mustard together to form a glaze.
Remove ham from the bag. Loosen the rind around the edges of the ham with a small sharp knife. Using a larger long bladed knife, remove rind in one large piece. Score the fat diagonally at 2cm intervals to form a diamond pattern. Stud with cloves, if using.
Place the ham in a large dish and pour glaze over the top to coat all over. Allow to stand in the refrigerator for 2 hours. Every 40 minutes, spoon the glaze that has pooled at the bottom of the dish over the ham.
Preheat oven to 220°C conventional / 200°C fan forced.
Place ham fat side up onto a roasting rack set over a baking tray. Fill base with ¾ cup water.
Pour any residual glaze over the top and cook for 30-40 minutes, or until golden brown. Sprinkle with the extra Chelsea Soft Brown Sugar in the last 10 minutes of cooking, to achieve a golden brown surface.
Carve ham and serve.