Cut the eggplant into bite sized cubes, and set aside in a bowl. Chop the onion and the garlic, and saute it in the olive oil until translucent. Drizzle the eggplant with olive oil, and mix together so that it is coated. The oil will absorb quickly. Add the eggplant to the onion mixture and cook over medium heat until the eggplant softens and begins to turn gold brown. Meanwhile, place the tomatoes in a bowl and crush them with your hands. Add the tomatoes to the eggplant, and then add the salt and pepper and basil leaves. Reduce the heat, and let simmer for about 15-20 minutes.
Bring a large pot of generously salted water to a boil. Cook the pasta until just shy of al dente and then drain it. Add the pasta to the skillet with the eggplant and tomatoes, and mix together over medium heat for about another minute. Serve immediately with a generous sprinkle of Parmigiano.