Preheat oven to 400°F. Lightly oil a three-quart baking dish.

Spread the eggplant pieces on a large rimmed baking sheet. Drizzle with three tablespoons olive oil and toss to coat. Roast, stirring occasionally, until tender and lightly browned, about 30 minutes.

Meanwhile, in a large, heavy saucepan over medium-high heat, warm the remaining one tablespoon olive oil. Add the sausages, working in batches if necessary, and cook, turning to brown on all sides, until no longer pink. Using a slotted spoon, transfer to a plate. Pour off all but two tablespoons of the fat in the pan.

Set the pan over medium heat, add the onion and cook, stirring, until tender, about five minutes. Stir in the garlic and cook until fragrant, about one minute. Add the wine, stir to loosen any browned bits on the pan bottom and bring to a boil. Stir in the tomatoes, Italian seasoning, and red pepper flakes and bring to a boil. Return the sausages to the pan and stir in the eggplant. Reduce the heat to medium-low and simmer until thickened, about 20 minutes. Stir in the olives and remove from the heat.

Meanwhile, bring a large pot of salted water to a boil over high heat. Add pasta and stir occasionally until the water returns to a boil. Cook according to the package instructions until not quite al dente. (The pasta will cook again in the oven, so do not overcook it now.) Drain well.

Add pasta to sauce along with ricotta and stir until combined. Adjust seasonings with salt and red pepper flakes. Spread pasta mixture in the prepared baking dish and sprinkle evenly with the mozzarella and Parmigiano-Reggiano. Bake until the sauce is bubbling, the mozzarella is melted, and the Parmigiano-Reggiano is golden, about 20 minutes. Let stand for five minutes, then serve.