Add cognac or brandy and use a wooden spoon to scrape up the brown bits. Turn heat back on to high to burn off alcohol, or light with a long stick match and stand back. If you choose to do this, make sure the heat is off completely. Bring to a simmer for a few minutes to reduce slightly. Add the wine, bring to a boil and then reduce to a simmer for another 10 minutes. Add the remaining fresh thyme leaves, bay leaves and about 3/4 of the cooked pancetta, reserving some to garnish at the end. Add the chicken stock and the pieces back to the pot (all but breasts, hold this aside so they don’t get overcooked and stringy). Make sure tops of chicken pieces are not submerged to braise. Bring to a simmer and cover. Place in the oven and cook for 20 minutes.