If you're using an oval casserole dish, it's very possible that you'll have some vegetables left. I usually take about 1/2 cup of sauce from the big casserole dish (it won't look like much sauce at the beginning, but remember that the vegetables release lots of water so there will be lots of liquid at the end) and add it to a smaller baking dish, along with the leftover vegetable slices. If you don't have any sauce left, but you have the vegetable slices, you can bake the vegetables alone, with or without the cheese. Just season them well with salt, pepper, Herbes the Provence, and olive oil. Bake the same way as the other dish.