In southern France a “tian” refers to both an earthenware casserole and the actual vegetable-centric dish. A tian is a wonderful way to make the most of summer produce and leftover chicken; use this version as a base for jumping off to create your own favorite combinations.
Heat oven to 375˚F. Lightly brush a 2-quart baking dish or casserole with oil. Heat 1 tablespoon oil in a medium skillet over medium-high heat. Add shallots and garlic; sauté about 6 minutes. Spoon into the bottom of the baking dish.
Spread the chicken on top of the shallot mixture in an even layer.
Begin arranging the sliced vegetables, alternating the layering in a concentric circle or in rows on top of the chicken. Fit them in tightly in a single layer. Drizzle with 2 tablespoons oil and season with salt and pepper. Sprinkle with fresh thyme.
Cover the baking dish with foil; bake 40 minutes or until the potatoes are tender. Mix the bread crumbs and cheese; season with salt and pepper. Sprinkle mixture over the top of the casserole.
Bake, uncovered, for about 15 minutes or until golden brown. Garnish with thyme sprigs.