Preheat oven 325°F.
Remove leaves from rosemary and mince. Keep both leaves and stem.
Heat 1 teaspoon olive oil in 12 inch ovensafe skillet over medium heat until oil is shimmering. Add pancetta and cook until just starting to brown, about 2-3 minutes. Add garlic slices and cook, stirring until garlic is golden brown. Do not burn. Remove pancetta and garlic using slotted spoon and keep for later.
In the same pan, increase the heat to medium high and add 2 tsp olive oil and heat until just smoking. Pat chicken dry with paper towel and sprinkle both sides with generous amount of pepper and bit of salt. Add chicken skin side down and cook without moving until nicely browned, about 6-8 minutes. Turn chicken and brown on second side for about 5 minutes longer. Transfer chicken to plate.
Remove all but 2 T fat from pan. Sprinkle flour over fat and cook, stirring for about 1 minute and slowly add wine and chicken broth. Bring to simmer, scraping bottom of pan with wooden spoon to loosen browned bits and cook until liquid is slightly reduced, about 3 minutes.
Stir in cloves, rosemary stem, sage, bay leaves, red pepper flakes and reserved pancetta-garlic mixture. Nestle chicken into liquid skin side up. Skin should be above the surface of liquid to keep it crisp at all times and bake, uncovered, until meat offers no resistance when poked with fork, about 1 hour. Check chicken after 15 minutes in the oven; broth should be barely bubbling and if bubbling too much, reduce oven temperature to 300 degrees F.
Using tongs, transfer chicken to serving platter and tent with foil to keep warm. Remove and discard rosemary stem, cloves, and bay leaves. Place skillet over high heat and bring sauce to boil. Cook until sauce is reduced to about 1 1/2 to 1 1/4 C, about 2 to 4 minutes. Turn off heat and stir in rosemary leaves, lemon juice and butter. Taste for salt and pepper. Pour sauce around chicken and serve.