Heat 1 tbsp of the oil in a large casserole over a low heat and add the lardons or pancetta. Cook until they are golden and slightly crunchy. Remove from the casserole dish with a slotted spoon and sit on a piece of kitchen paper.
Toss the chicken in the flour and season well with salt and pepper. This can either be done in a bowl or, to make the job really easy, toss together in a large freezer bag. Add to the casserole dish and fry over a high heat until browned all over. Remove from the casserole and then add the remaining 1 tbsp of oil.
Add the shallots, celery and carrot and cook for a few minutes until the shallots are softened, then return the lardons and chicken to the casserole, along with the bay leaf, tomato puree and chicken stock. Stir to mix everything together, and then bring to the boil. Cover with a lid and place in the oven for 30- 40 minutes.
While the casserole is cooking you can prepare the dumplings.
Place the flour, breadcrumbs and butter in a food processor and blitz to a crumb consistency. Add the cheese, thyme, eggs and seasoning. Briefly blitz until the mixture forms a fairly moist dough. Using floured hands, shape the dough into 12 even sized balls.
After 30 minutes of cooking the casserole, remove from the oven and stir in the Broccolini. Sit the dumplings on top and return the casserole to the oven for a further 10-15 minutes, without the lid this time, until the dumplings are lightly and golden. Serve hot.