This is a time-consuming recipe but well worth its colorful result.

2 lb of eggplants
2 cups of onions, sliced
2 Tbsps of olive oil
2 cans of peeled italian tomatoes (1lb each)
Thyme, orange peel, saffron, garlic
Salt and pepper
8 oz of sliced swiss cheese 

• Cook onions in olive oil, covered, for 8 to 10 minutes.
• Drain the tomatoes, reserve the juice.
• Rub the pulp trough a sieve to eliminate the seeds.
• Stir the pulp into the onions and add herbs, orange peel, saffron, garlic, salt and pepper.
• Cover the pan and simmer for 45 minutes.
• The sauce should be thick enough to hold its shape in a spoon.
• In a big pan boiled some salted water.
• Cut eggplants in halves then in slices.
• Blanch the slices in boiling water for 2 minutes and drain on paper towels.
• Saute the slices in olive oil until slightly browned and put them on a tray.

• In a gratin dish arrange in layers – slices of eggplants, tomato sauce, and swiss cheese.
• Repeat until all slices are used.
• Reheat oven 375°F and bake 35 minutes covered, then 10 more uncovered.
• Use the reserved juice of the tomatoes if the dish looks too dry while cooking.

See also Tian d’aubergines.