Generously rub a 5 cup gratin dish with garlic. Grease lightly with about 1 teaspoon of the oil.

Layer half of the potatoes in bottom of dish, overlapping slices if necessary. Season lightly with the thyme and salt. Drizzle with 1 tablespoon of oil over the potatoes.

Add a layer of half the red peppers, then half the zucchini. Season again with salt and thyme. Drizzle 1 tablespoon oil over the vegetables. Repeat layering and seasoning. Drizzle any remaining oil over the top.

Cover securely with tin foil. Bake until vegetables are very soft and tender, about 1 hour. Serve immediately. (Serves 4)