Method

1. Place the gammon joint into the large AGA preserving pan and cover with water, bring to the boil. Drain off all the water and rinse the meat. Replace in the clean pan and add the quartered onions, cider, water, parsley and peppercorns. Cover with the lid and bring to the boil, simmer for 15 minutes.

2. Place on the floor of the Simmering Oven and simmer for 3 hours. Remove the gammon from the liquid, cool a little and remove any string. Take a sharp knife and peel off the rind. Score the fat into a diamond pattern.

3. Place the gammon onto a piece of Bake-O-Glide in the AGA roasting tin then spread ready-made mustard thickly over the fat and press Demerara sugar all over the mustard. 

4. Slide the tin on the lowest set of runners in the Roasting Oven and cook until the top is nicely browned, about 15-20 minutes.

5. Meanwhile make the garnish. Cut the small tangerines into quarters. Melt the butter and sugar together and cook until it just begins to turn golden, then add the tangerine quarters.

6. Cook until the tangerine skins just begin to brown, then add the cherries and cook for a further 2 minutes. 

7. Place the gammon on a serving dish and garnish the diamonds of fat with the tangerines and cherries, fixing them with part of a cocktail stick if necessary (don’t forget to discard the cocktail sticks before carving!).

Conventional cooking: Simmer the gammon joint on the hob and finish off in a hot oven, 200°C (400°F), Gas Mark 6.