Cut the chicken into medium sized pieces and season well, dust lightly with flour

Dice the carrot, celery, garlic and shallots into medium sized pieces and set aside.

Cut the potato into 1cm thick discs. Combine the milk, flour and 2 minced cloves of garlic in a bowl, grate over a pinch of the nutmeg and add to a sauce pan with the potato so it's covered. Simmer for 10 minutes.

Meanwhile, heat some butter and oil in a large iron pan over a medium-high heat and add the chicken. Brown for around 3 minutes each side, then remove from the pan and set aside.

Reduce the heat to medium and add more oil. Add the chopped vegetables and brown for 3-4 minutes.

Deglaze the pan with the wine, scraping all the fond from the pan and combining with the liquid. Add the chicken stock and simmer for 10-15 minutes until reduced by 2/3rds.

Once the potatoes have simmered, coat a small casserole dish with melted butter and pour over enough of the milk/cream mixture to cover the bottom of the dish. Add a thin layer of the potatoes so they overlap but aren't stacked. Once covered, season with salt, pepper and grated hard cheese. Repeat this until all the potatoes are used. Cover with the remaining liquid and a generous coating of cheese. Add to the oven at 150 degrees for 45 minutes.

Once the broth has reduced, strain over a sieve and discard the vegetables. Return to the pan. When it begins to boil, add the cream and whisk through. Add the mustard and season to taste. Return the chicken to the pan to keep warm. Top with fresh herbs.

Remove the potatoes from the oven. If they aren't browned enough, turn the heat up and return for a further 5 minutes. Use a spatula to slice into rectangles and add to a plate.

Serve the chicken, covered with the sauce with the potatoes on the side.