1. Pat the pork cheeks dry with kitchen paper and season generously with salt and black pepper.
2. Heat the olive oil in a heavy casserole dish over a medium-high heat. Brown the pork cheeks well on all sides, working in batches if needed. Lift them out and set aside.
3. Reduce the heat to medium. Add the butter, onion, carrot and celery to the same pan. Cook for 8–10 minutes, stirring often, until softened and lightly golden.
4. Stir in the garlic and tomato purée, then cook for 2 minutes until fragrant and slightly darkened.
5. Pour in the white wine and scrape the base of the pan to lift all the browned bits. Let it bubble for 3–4 minutes until reduced by about half.
6. Return the pork cheeks to the pan. Add the stock, Dijon mustard, bay leaves, thyme and rosemary. The liquid should come roughly halfway up the cheeks; add a splash more stock if needed.
7. Bring to a gentle simmer, then cover with a lid and transfer to the oven at 150°C fan / 170°C / gas 3 for 2½–3 hours, turning the cheeks once halfway through. They are ready when very tender and yielding to a spoon.
8. While the pork finishes cooking, make the mash. Put the diced celeriac in a pan of salted boiling water and cook for 15–20 minutes, until completely tender.
9. Drain the celeriac very well, then return it to the hot pan for 1–2 minutes to steam off excess moisture.
10. Mash or blend the celeriac with the butter, double cream, Dijon mustard, salt, pepper and a little nutmeg if using. Keep warm.
11. Remove the pork cheeks from the casserole and keep warm. Discard the bay leaves and herb stalks. Simmer the sauce on the hob for 8–10 minutes until glossy and slightly thickened.
12. Stir in the cider vinegar, then taste and adjust the seasoning. Add a little more vinegar if the sauce needs lifting.
13. Spoon the celeriac mash onto warm plates, top with the pork cheeks, and ladle over the sauce. Finish with chopped parsley.

Multi-Cooker Option

Ninja Foodi / Air Fryer

1. Use the Sear/Sauté function to brown the pork cheeks in oil, then remove them.
2. Sauté the onion, carrot, celery, garlic and tomato purée as above.
3. Deglaze with the white wine, then add the stock, mustard and herbs.
4. Return the pork cheeks to the pot.
5. Cook on Pressure Cook High for 45 minutes, then allow a natural pressure release for 15 minutes.
6. Remove the pork and reduce the sauce using Sear/Sauté until glossy.
7. Pork cheeks should be fully tender and well above 70°C internal temperature, though texture is the real guide here; they should pull apart easily.

Air Crisp finish

This dish does not need crisping, but if you like a slightly caramelised edge, place the cooked cheeks in the basket and use Air Crisp at 190°C for 3–4 minutes, brushing lightly with reduced sauce first.