Chicken Cacciatore

. olive oil

. raw chicken breasts (, boneless, skinless, cut into 1-inch pieces)

medium onion (, thinly sliced)

medium celery stalk (, sliced)

garlic (, finely chopped)

medium red bell pepper (, cut into 1-inch pieces)

. sliced mushrooms

whole tomatoes

. dried basil (, crushed)

Ground black pepper ((to taste; optional))

medium zucchini (, sliced)

medium eggplant (, peeled, cut into 1-inch cubes)

fresh parsley sprigs (, finely chopped (for garnish, optional))