Heat 1 tbsp oil in a large, deep flameproof roasting tin or in your largest flameproof casserole dish. Season the beef well and sear in the tin until nicely browned all over. Meanwhile, mix the paprika, mustard powder, onion powder, cinnamon, cloves, 2 tbsp sugar, 2 tbsp honey and 2 tbsp of the whiskey in a small bowl with a generous amount of salt and pepper. Lift out the beef and scatter the onions and bay leaves over the base of the dish, pour in 100ml water and put the beef back on top. Brush the spice paste all over the meat. Will keep chilled for up to a day.
Heat oven to 150C/130C fan/gas 2. Wrap the tin tightly in a few sheets of foil, or cover with a lid, and bake for 6-7 hrs, turning once or twice during cooking, spooning the juices over the meat and topping up with a splash more water if the bottom of the pan is dry.
Increase the temperature to 200C/180C fan/gas 6. Toss the carrots with the onions around the beef, season then cover again with the foil. Pierce the potatoes a few times each and place on the shelf below the beef. Cook for a further 45 mins.
Meanwhile, pour the remaining sugar, whiskey, honey and vinegar into a pan. If there is lots of liquid in the tin, add most of this too (but leave some so the meat doesn’t dry out). Season and bubble to make a sticky glaze. Uncover the meat and carrots, brush with the whiskey glaze and cook for another 15 mins until the meat is dark, glossy and very tender, and the carrots and potatoes are soft. Remove from the oven, cover the meat loosely with foil and leave to rest for 15 mins.
Put the potatoes in a bowl and, when cool enough to handle, use kitchen scissors to cut them into pieces – you want to keep the skin in the mash for extra flavour but any big bits will be chewy so try to break it down as much as possible with the scissors, then mash well with a potato masher. Add the soured cream, butter, milk and most of the chives, season really well and mash again. Transfer to a bowl and top with a knob of butter and the remaining chives. To serve, either cut into thick, tender slices or shred the meat with two forks, discarding any string as you go. Serve with the mash, carrots and onions and spoon over the juices.Watch our video on how to tie a butcher’s knot.