In large pot, bring 4 quarts of water to a boil for the pasta. Meanwhile, in a large skillet, warm 3 tablespoons olive oil over medium heat. Add eggplant and cook, stirring frequently, until it starts to soften and brown, about 10 minutes. Add half of garlic and all the rosemary and cook until the garlic is slightly golden, about 2 minutes. Season with salt and pepper. In a medium non reactive skillet, heat remaining three tablespoons of olive oil. Add tomatoes and cook over high heat, tossing until slightly softened, about three minutes. Stir in remaining garlic and season with salt and pepper. Salt the boiling pasta water. Add the penne until al dente about 13 minutes. Drain the pasta and return it to the pot. Add the ricotta salata and toss. Add the eggplant and toss again. Add the tomatoes and toss gently. Transfer the pasta to a large warmed bowl or platter and serve immediately.