Pre heat oven to 160c.
Coat chicken in flour, reserving excess flour.
Heat oil in a large, heavy-based flameproof casserole dish and brown chicken all over, then remove to a plate.
Add leek, carrot, potatoes and garlic and fry for 1-2 mins.
Add remaining flour and fry for a further 1-2 mins.
Add wine and simmer for 1-2 mins, scraping any brownings from the base of the pan.
Stir in Dijon mustard, add chicken and stock and bring to a simmer.
Bake, covered for 1 hour.
**if making 2 Way Dinner remove 500g of chicken (shred) & 1 1/2 cups of sauce (without veg)**
Remove from oven. Stir through French mustard and rosemary.
Simmer on stove uncovered for 20 mins then serve.