If you don't have a shallow baking dish, you can use a 9-inch square baking dish.
- 3 tablespoons extra-virgin olive oil
- 1 small onion, halved and thinly sliced
- 1 large garlic clove, thinly sliced
- 1 tablespoon fresh oregano
- Coarse salt and freshly ground pepper
- 2 medium carrots, sliced diagonally 1/8 inch thick
- 1 medium zucchini, sliced 1/8 inch thick
- 1 medium Red Bliss potato, sliced 1/8 inch thick
Preheat oven to 425 degrees. Drizzle 1 tablespoon oil in a shallow 2-quart baking dish. Add onion, garlic, and oregano, and toss to coat. Season with salt and pepper.
Arrange remaining vegetables over onion mixture, alternating carrots, zucchini, and potato, and overlapping each. Drizzle with 1 tablespoon oil; season with salt and pepper. Cover with parchment, then foil. Roast in oven for 20 minutes. Uncover, drizzle with remaining tablespoon oil, and roast, basting with pan juices every 10 minutes, until tian is light gold, about 25 minutes. Let cool slightly; serve.