Bring a large pot of salted water to a rolling boil. Add the rigatoni and cook according to package directions until just al dente (about 10-12 minutes). Drain the pasta and set aside; do not rinse.
In a large skillet, heat the olive oil over medium heat. Add the minced garlic and sauté for 1-2 minutes until fragrant but not browned. Stir in the chopped sun-dried tomatoes and red pepper flakes (if using), cooking for another 1-2 minutes.
Add the marinara sauce and Italian seasoning to the skillet with garlic and sun-dried tomatoes. Stir well and simmer gently for 3-5 minutes. Season with salt and pepper to taste.
Combine the cooked rigatoni with the sauce mixture in a large bowl or directly in the baking dish, tossing until evenly coated.
Layer half of the sauced rigatoni in the baking dish. Sprinkle half of the shredded mozzarella and grated Parmesan evenly over the pasta. Add the remaining rigatoni on top, then finish with the rest of the mozzarella and Parmesan cheeses.
Preheat the oven to 375°F (190°C). Bake uncovered for 20-25 minutes until the cheese is melted, bubbly, and golden on top.
Remove from the oven and let cool for a few minutes. Garnish with fresh basil leaves. Serve warm and enjoy!
