Bring a large pot of salted water to a boil. Add the ziti and cook until al dente. Drain and set aside.
Heat the olive oil in a large skillet over medium heat. Add the sausage and cook, breaking it up with a spoon, until browned.
Stir in the minced garlic and oregano. Cook for one minute, then add the marinara sauce. Season with salt and pepper. Simmer for five minutes.
Remove the skillet from heat and stir the drained ziti into the sauce until evenly coated.
Spread half the ziti mixture into a baking dish. Dollop the ricotta over the top in small spoonfuls. Add the remaining ziti mixture.
Sprinkle the mozzarella and Parmesan evenly over the surface. Bake at 375°F for 25 minutes until the cheese is melted and lightly golden.
Let the dish rest for five minutes, then scatter fresh basil leaves on top before serving.