1. Preheat the oven to 350F. Place the chicken pieces in a large paper bag with the flour, close and shake to coat. Remove the chicken from the bag and shake off excess flour.
2. Heat the oil in a large Dutch oven. Add the chicken, in batches if necessary, and cook, turning once, until browned, about 10 minutes. Transfer to a plate.
3. Add the garlic to the pot and cook, stirring occasionally, until golden, about 3 minutes. Add the onion and cook until lightly browned, about 7 minutes. Add the zucchini, tomatoes and rosemary and cook, stirring, until the zucchini is fork-tender, about 5 minutes. Add the broth and olives (if using) and bring to a boil.
4. Return the chicken to the pot and bring to a boil over high heat. Cover, transfer to the oven and bake the chicken until the juices run clear when pierced with a knife, about 30 minutes.
5. Transfer the chicken and vegetables to a serving plate and spoon the cooking broth over the top.
Tip: Peeling Tomatoes
To peel tomatoes easily, cut an X through the skin on the bottom of each and drop into a pan of boiling water for a few seconds. Transfer to a bowl of cold water with a slotted spoon and let cool. Use a paring knife to slip the skins off.
Technique: Flouring Chicken