Place gammon in a large pot with ginger, vegetables, and spices. Pour in ginger beer and stock. Bring to a boil, reduce heat, and simmer for 2 hours, until tender. Remove from liquid and cool slightly. Remove skin, leaving fat layer. Score fat in a diamond pattern.
Mix all glaze ingredients in a bowl. Preheat the oven to 180°C. Place the gammon in a roasting pan and brush with glaze. Roast for 30 minutes, basting every 10 minutes, until golden.
Bring stock to boil in a large pot. Gradually whisk in polenta, stirring constantly. Reduce heat and cook for 20-25 minutes, stirring frequently. Add cream, butter, and parmesan—season with salt and pepper. Keep warm, adding extra stock if needed.
For the apple chutney, Combine all ingredients in a saucepan. Bring to a boil, reduce heat, and simmer for 45 minutes until the apples are soft and mixture is thick. Remove the cinnamon stick. Cool before serving.
Strain 500 ml of gammon cooking liquid into a saucepan. Reduce by half. If desired, thicken with 1 tbsp cornflour mixed with water. Season to taste.