Yes - it's exactly as it sounds! I have Nigella to thank for this one (as I do for many of my recipes) but I have put my own spin on it. I make this every Christmas and usually serve it with some creamy potato dauphinoise, however it would also go well with roast potatoes, roast vegetables (especially parsnips) or mashed potatoes. It is pretty much impossible to go wrong with this one but I will give you the same advice that the lovely Nigella gives.....do not even consider using diet coke!!
Gammon (I trust you to use the size you need depending on how many you are serving and adjust the quantities below accordingly - I use a small piece of gammon which serves two people)
1 litre of coke
2 tablespoons of treacle
2 teaspoons of mustard powder
2 teaspoons of brown sugar
2 teaspoons of mixed spice
Put the gammon in a large pan with the coke and the quartered onion.
Bring to the boil then reduce the heat, cover and simmer for 1 hour.
Preheat the oven to 220 Degrees (if you are making the gammon ahead don't put your oven on at the moment, just leave the gammon in the coke until you are ready to bake it but increase the oven time to 40 minutes or so, until it is heated right through).
Put the gammon in an oven proof dish and spread the treacle over the skin, followed the the rest of the glaze ingredients sprinkled over.
Cook for 15 minutes then leave to sit for 5 minutes or so before slicing and serving.