Pre-heat oven to 400°F.
Season the chicken with salt and pepper.
Put the flour in a shallow pan and lightly dredge the chicken in it, shaking the pieces to remove excess flour.
Swirl the oil in a large roasting pan; place the floured chicken in the pan.
Season the chicken with the Herbes de Provence.
Arrange the lemon, garlic cloves and shallots around the chicken; add the vermouth to the pan.
Put the pan in the oven and roast for 25 to 30 minutes; remove from oven and baste chicken with the pan juices.
Return to oven and continue roasting for another 25 to 30 minutes, or until the chicken is very crisp and the meat cooked through.
Serve in the pan, or on a warmed platter, garnished with the thyme.