- In a small saucepan, soften the onion and garlic in the oil. Add the tomatoes. Bring to a boil and simmer over low heat for about 12 minutes. Season with salt and pepper. In a blender, purée the tomatoes. Adjust the seasoning. Set aside.
- With the rack in the middle position, preheat the oven to 180 °C (350 °F). Dust the eggplant slices with flour. In a large skillet, brown the eggplants, two at a time, on both sides in the oil. Season with salt and pepper. Let cool.
- Place the eggplant slices on a work surface. Top with a slice of mozzarella cheese and roll. Wrap each roll with a slice of prosciutto.
- Spread half the sauce into a 23 x 13-cm (9 x 5-inch) baking dish. Add the rolls, side-by-side, and cover with the remaining sauce. Sprinkle with the Parmigiano-Reggiano cheese. Bake for about 10 minutes and brown under the broiler, as needed. Sprinkle with the basil and serve as an appetizer.