Place the gammon in a large saucepan, cover with water, bring to the boil then drain. Rinse the gammon and return to the pot. Add the onion, celery, carrot, Cardamom Pods, ginger and peppercorns. Pour over the blueberry juice (reserving 200ml for the glaze) and top up with water if necessary so the gammon is just covered. Bring to the boil, skim the surface and reduce the heat to a simmer, cover and cook for 2 to 2 ½ hrs, until the meat is tender. Leave to cool in the cooking liquor.
Pre-heat the oven to 220°C, 425°F Gas Mark 7. Remove the joint from the pan, reserving the cooking liquor for the lentils. Once cool enough to handle, carefully cut the skin off the ham, making sure to leave a layer of fat, lightly score the layer of fat into diamond shapes. Line a roasting tin with foil and place the joint on top. Warm the honey, mustard and reserved blueberry juice in a pan and bring to the boil. Spoon over the fat and bake for 20-25 minutes or until the glaze has caramelised. Allow to cool before slicing. Serve with cardamom and blueberry braised lentils.
For the Cardamom and blueberry braised lentils:
Heat the olive oil in a large saucepan over a medium heat. Add the carrot, onion, celery, garlic, chilli and Cardamom, cook for 5 minutes, until the vegetables begin to soften, meanwhile place the lentils in a fine mesh colander and rinse well under cold water, drain before adding to the vegetables.
Add the hot stock, bring to the boil, then reduce the heat and simmer for 20-25 minutes or until the lentils are al dente and most of the liquid has been absorbed. Add a little more ham stock if the lentils look a little dry during cooking.
Remove from heat; season with sea salt and pepper, cool a little before stirring through the blueberries and parsley. Serve warm or at room temperature with sliced glazed ham.