Lightly crush the fennel, garlic and the leaves of 3 thyme sprigs together in a pestle and mortar. Add 1 tbsp oil and season well, then bash to a rough paste. Rub the mixture all over the pork, then cover and chill for at least 2 hrs or up to 24 hrs.

Set the slow cooker to low. Tip the shallots into a heatproof bowl and pour a kettleful of boiling water. Leave to soak for 2 mins, then drain and rinse under cold water until cool enough to handle (this will make them easier to peel). Cut off the roots and remove the papery skins.

Heat the remaining oil in a frying pan or flameproof casserole that's large enough to fit the pork joint. Brown the shallots for a few minutes over a medium heat, then tip into the slow cooker. Add the celeriac and apples, then season well and mix.

Put the pork in the pan and brown really well on all sides, then transfer to the slow cooker fat-side up on top of the vegetable mixture. Pour the wine into the pan and bubble for 1 min. Add the stock, honey and mustard and bubble for 1 min more, then pour the mixture over the pork. Cover and cook on low for 5-6 hrs, turning the meat and stirring the veg halfway through cooking, if you can.

Lift the pork out of the slow cooker, wrap and leave to rest for 10 mins before carving. Serve with the cooked vegetables and some greens, if you like.