This gorgeous layered vegetable gratin requires 3 hours in the oven for its alchemy to work. A tian is an earthenware baking dish but you can use a small paella pan or any dish with a 10-cup capacity. The delicious liquid that accumulates in the dish can be used to make a vinaigrette. Serve the tian hot or at room temperature.
Ingredients:
- 1 large eggplant (about 1.5 lb), peeled
- 4 medium onions, about 1.5 lb
- 5 large ripe tomatoes, about 2 lbs
- 2 tbsp fresh thyme leaves
- 2.5 tbsp dried oregano
- 10 tbsp freshly grated Pecorino Romano
- 1/2 cup olive oil
Preheat the oven to 300 F. Slice the eggplant into thin rounds. Toss with one tbsp salt. Thinly slice the tomatoes. Thinly slice the onions, keeping the slices intact.
Arrange half of the eggplant in the bottom of a tian or paella pan. Top with an overlapping layer of half the tomatoes, and then half the onions.

