Put the pancetta in a large cold frying pan and put over a heat. Fry until the fat comes out and the pancetta is crisp. Scoop out with a slotted spoon onto a plate, leaving behind any fat. Tip in the shallots and cook for 10-15 minutes until golden brown all over. Add the sprouts for the final 5 minutes, turn up the heat and cook until caramelised and browned a little. Lower the heat and add the calvados, cider vinegar, honey and 50ml of water, add the pancetta back to the pan and cook gently for 10-15 minutes until the shallots and sprouts are tender and the sauce glazes the veg.