Heat the oil in the casserole on the hob over a medium heat, add the bacon and cook until crisp.

Drain the cooked bacon into a dish retaining the oil in the casserole. Add the butter to the oil and cook the shallots until nicely browned. Add the pork a little at a time, allowing each batch to colour slightly before adding the next.

Once all the meat has been added and coloured pull the pan away from the heat. Pour over the calvados and carefully ignite, standing well back until the flames subside. (See cook's notes).

Place the pan back over the heat, add the celery, chopped apple, mustard, pepper, herbs and stock, stir well to release any caramelized pieces from the base. Bring to a gentle simmer, place on the lid and transfer to the oven to cook for 2 hours.

Skim away the excess fat from the top of the casserole and discard.

Stir in the creme fraîche along with the cornflour and water mixture. Return the casserole with the lid on to the oven for 15-20 minutes to thicken.

Heat the butter in a small frying pan and gently fry the sage leaves until crisp.

Remove the casserole from the oven, stir the contents and adjust the seasoning to taste with some pepper and salt if needed. (See cook's notes).

Serve the casserole decorated with the crisp sage leaves on top. Accompany with simply prepared potatoes, boiled or mashed, green vegetables and some crusty bread.

Igniting the alcohol is termed to flambé; it should be done carefully using a long match or barbecue lighter. Have the means of ignition ready before you start or the brandy will soak into the meat and juices and may not ignite. Always light at the edge of the dish.If using a stock cube extra seasoning will probably not be required.