Preheat your oven to 425°F (220°C). Toss the diced eggplant with 2 tablespoons of olive oil, salt, and pepper. Spread the eggplant in a single layer on a baking sheet. Roast for about 25–30 minutes, stirring halfway through, until golden brown and tender.
While the eggplant roasts, heat the remaining 1 tablespoon of olive oil in a large skillet over medium heat. Add the diced onion and sauté until translucent, about 5 minutes. Stir in the minced garlic and cook until fragrant, about 1 minute.
Pour in the crushed tomatoes, then add the dried oregano, dried basil, salt, and pepper. Let the sauce simmer gently for 15–20 minutes to develop flavor.
Bring a large pot of salted water to a boil. Cook the rigatoni according to package instructions until al dente. Drain the pasta, reserving about ½ cup of pasta water.
Add the roasted eggplant to the simmering pomodoro sauce. Stir to combine and cook for another 3–5 minutes so the flavors meld. Toss in the cooked rigatoni, mixing well to coat the pasta in the sauce. If the sauce feels too thick, add a splash of reserved pasta water to loosen it up.
Plate the pasta and sprinkle generously with grated Parmesan cheese. Top with fresh basil leaves for a fragrant, colorful finish. Serve immediately and enjoy.
