Preheat your oven to 160c (320f)
Pat the beef cheeks dry with paper hand towels and season well with salt and pepper all over.
Heat 1tbsp of olive oil in a pan over medium - high heat and sear the cheeks all over until well browned. You might have to do it in a couple of lots or get two pans going to save time. Set aside.
Heat 1 tbsp oil in a heavy bottomed oven proof saucepan and fry the pancetta over medium - high heat for 10 mins until browned, lift out onto a plate with a slotted spoon, leaving the fat behind.
Add the onion, carrot, celery and a good pinch of salt and pepper and cook over medium heat until soft, around 10 minutes. Lower heat if it starts to brown and add more oil if it dries out. After 5 minutes add the garlic and herbs and continue cooking.
Add the wine and let it simmer for a minute or so.
Add the tomatoes and stock and bring to a simmer.
Add the beef cheeks and pancetta in. The beef should be mostly covered by liquid and just bobbing at the surface. Add more stock if you need, it's OK if they are poking out slightly.
Cover and cook in the oven for three hours, turning the beef cheeks over in the liquid half way through. At three hours pull one of them out, it should easily fall apart with two forks. If not then cook for a further 30 mins.
Once the beef is cooked remove the cheeks from the liquid and pull apart with two forks.
With a stick blender blend the liquid until smooth (so the onions, pancetta etc are blended into the sauce) This is optional if you want it a bit chunkier.
Add the pulled meat back in and and season to taste with salt and pepper. I like to add a big squeeze of lemon juice to liven it up and add some zing.
At this point if not using straight away you can take it off the heat, let it come to room temp then place it in the fridge until you want to use it. I always suggest making a meat sauce the day or two before to let the flavour come alive.