1. Mix parsley, lemon rind and garlic in small bowl. Cover and refrigerate while preparing chicken.Chicken:
2. Heat oven to 400 degrees F. Season chicken on both sides with salt and pepper.
3. Heat olive oil in large, heavy skillet over medium-high heat. When oil is hot, and working in batches to avoid crowding the skillet, add the chicken; saute for 3 minutes per side or until well browned. Remove chicken to a plate.
4. Add onions to skillet; saute until softened, 5 to 7 minutes. Add the garlic; saute for 1 minute or until fragrant, being careful not to burn the garlic. Add olives, lemon rind, thyme sprigs and the bay leaf.
5. Spread onion mixture in an even layer over the bottom of 13 x 9 x 2-inch glass baking dish. Arrange the chicken breasts in a single layer on top of the onion mixture. Pour in the chicken broth. Cover the baking dish tightly with aluminum foil.
6. Bake in 400 degree F oven 15 minutes. Remove foil from baking dish; bake 20 minutes or until instant-read thermometer inserted in center of chicken registers 170 degrees F.
7. Transfer chicken to platter; keep warm. Strain the braising liquid into small saucepan. Remove and discard the rind, bay leaf and thyme. With slotted spoon, transfer remaining onion mixture to platter with chicken. Over medium-high heat, simmer braising liquid until reduced by half, 8 to 10 minutes.
8. To serve, place the chicken on plates. Pour the sauce over the chicken. Sprinkle with the gremolata. Serve with polenta or mashed potatoes for soaking up the sauce if desired. Makes 6 servings.