Tian is a provençal word often used to describe a casserole of vegetables which can include meat or fish as well.  Eggplant and tomato is a favorite combination of vegetables in the South of France.

It is a good idea to use a covered casserole dish that can go from oven to the refrigerator or even to the microwave, since this dish can be served hot, cold, or reheated.

2 medium eggplants (or 4 small ones)
4 tomatoes, sliced
2 onions, peeled and sliced
6 Tbsp of olive oil
2 Tbsp of balsamic vinegar
1 Tbsp of Dijon mustard
Salt and pepper

• Lightly oil a gratin dish and spread the sliced onions at the bottom.
• Slice the eggplants but do not cut all the way through.
• Put a slice of tomato between each cut of the eggplants.
• Slicing the tomatoes in a slant will permit a better fit when layering them into the cuts of the eggplants.
• Make sure that the top of each tomato is flush with the top of the eggplant to make a nice presentation.
• Arrange both eggplants, layered with the tomatoes, on top of the sliced onions.
• Make a vinaigrette sauce sauce by mixing the mustard and vinegar and add the oil.  Season with salt and pepper.
• Dribble the vinaigrette all over the eggplants.
• Cook, uncovered, for an hour.
• Then cover with aluminum foil or with the cover of the dish, and cook for another 45 to 50 minutes.