Tip the beans into a large pan, then pour in enough water to cover the beans by 5cm. Add the bay and leave to soak overnight. The next day, drain the beans, return to the pan and pour in enough fresh water to cover the beans by 3cm. Bring to the boil, reduce the heat to a simmer and cook for 20 mins until the beans are tender (you may need to top up the water slightly as they cook).
Heat the oven to 140C/120C fan/gas 2. Heat the oil in a large casserole or ovenproof saucepan, and fry the beef for 5 mins over a high heat until evenly browned (you’ll need to do this in batches). Transfer to a plate using a slotted spoon. Add the lardons and onion to the pan, and cook over a medium- high heat for 5-7 mins until the onions are turning golden and the lardons are starting to crisp.
Stir the beef back into the pan. Add the beans along with the cooking liquid, and stir in the garlic, treacle, tomato purée, mustard powder and cloves. Season, then top up with some water so the beans are covered by 2-3cm. Cover and bring to a simmer, then transfer to the oven for 2 hrs 30 mins. Remove the lid, stir and return to the oven for 1 hr 30 mins until the meat is tender and the sauce rich. Once cooled, the beans can be frozen for up to three months (see below). Serve with jacket potatoes or bread and coleslaw.
