Preheat the oven to 350°F. Grease a large baking dish.
Core tomatoes and scoop out seeds, leaving tomato wall at least ¼-inch thick. Place tomatoes in the prepared baking dish.
In a bowl, combine chicken, celery, chervil, basil, and thyme, and mix well. Add cream and toss until everything is coated. Season with salt and pepper.
Spoon chicken mixture into tomato shells. Dot the top of each tomato with butter and bake for 20 minutes. Garnish with parsley.