Salt the eggplant slices on both sides and allow to stand for 20 minutes. Pat them dry and brush generously with olive oil. Place on a baking sheet and roast them for 20-30 minutes, until tender.
In a large skillet heat the remaining olive oil add the sausage, onion and garlic. Cook, stirring occasionally until fragrant and the sausage has begun to brown. Stir in the chopped tomatoes, salt and pepper and cook another 2-3 minutes, until the mixture comes to a boil. Remove from heat.
Lay a single layer of roasted eggplant on the bottom of a lightly buttered, large baking dish. Top with half of the sauce followed by half of the Parmesan. Layer on the remaining eggplant, then the remaining sauce. Sprinkle with the bread crumbs and remaining Parmesan.
Bake uncovered for 30-35 minutes, until the edges begin to bubble and the bread crumbs are golden brown