1-Preheat the oven to 400°F (200°C). Slice the eggplants into 1/2-inch thick rounds and lightly brush both sides with olive oil. Lay them on a baking sheet and roast for 20-25 minutes until golden and tender.

2-While the eggplant roasts, prepare the marinara sauce by heating it gently with minced garlic and fresh basil for enhanced flavor.

3-In a greased baking dish, spread a thin layer of marinara sauce. Arrange a layer of roasted eggplant slices over the sauce.

4-Sprinkle shredded mozzarella and grated Parmesan evenly over the eggplant layer.

5-Repeat layering with sauce, eggplant, and cheeses until all ingredients are used, finishing with a breadcrumb topping for crunch.

6-Bake uncovered at 375°F (190°C) for 25-30 minutes until the cheese bubbles and the topping is golden brown.

7-Let the gratin rest for 10 minutes before serving. For dietary adaptations, use vegan cheese in the layering steps or gluten-free breadcrumbs on top. To reduce calories, substitute part-skim cheese and use less oil for roasting.