Preheat the oven to 160ºC/325ºF/gas 3. Cover the porcini with boiling kettle water and leave to rehydrate. Season the beef cheeks with sea salt and black pepper, then brown them in a large casserole pan on a high heat with a splash of oil, turning until well coloured all over. Meanwhile, slice the pancetta into lardons. Peel the celery, onions and carrots, then chop into rough 1cm dice. In a pestle and mortar, crush the cloves with 1 teaspoon each of salt and pepper, then peel and pound in the fresh garlic.
When brown, push the cheeks to one side of the pan and reduce to a medium heat. Add the pancetta and cinnamon, stirring until the pancetta is lightly golden. Drain the porcini, reserving the liquor, then roughly chop and add to the pan with the veg. Tie the herbs together, then stir in with the garlic mixture. Fry for 15 minutes, or until soft, stirring occasionally.
Pour in the wine, let it reduce by half, then pour in the reserved porcini water (discarding just the last gritty bit) and the passata. Fill the passata bottle with water and pour into the pan. Cover with a scrunched-up sheet of wet greaseproof paper and a lid. Cook in the oven for 4 hours, or until the meat is outrageously tender and the sauce has thickened. Taste the sauce and season, if needed, then serve up however you wish.