Potato and onion tian

Ingredients:

• 6 tbsp extra-virgin olive oil, plus more for greasing the pan
• 900 g potatoes (4-5 pcs.), cut into thin circles
• 2 teaspoons fresh thyme
• 1 sweet onion, sliced ​​into 0.3-0.5 cm thick circles.
• 1 leek (white and light green parts only), sliced ​​into 0.3-0.5 cm thick circles.

Preparation:

1. Preheat oven to 220°C (425°F). Grease a 3-quart (1-liter) oval baking dish with olive oil. In a large bowl, toss the potatoes with 1 tablespoon of olive oil, thyme, 1/2 teaspoon of salt, and a few grinds of black pepper.
2. In a separate bowl, toss the onion and leek slices, without separating them into rings, with 1 tablespoon olive oil and a large pinch of salt and black pepper.
3. Arrange the potatoes, onions, and leeks, overlapping each other, in the prepared dish. Drizzle with the remaining 1/4 cup olive oil and sprinkle with 1/2 teaspoon salt. Cover with foil and bake until the vegetables are very tender, about 45 minutes. Remove the foil and bake until the potatoes are golden brown and crispy around the edges, another 30 to 40 minutes. Let the casserole rest for about 10 minutes before serving.