Look for Ziti Rigati, or ridged ziti—the chunky sauce will adhere better than it will to the smooth variety. The addition of eggplant adds hearty texture to the rich sauce and makes it distinctly Sicilian.
If using the sausage, heat the oil in a large skillet over medium heat. Add the sausage and cook until browned. Transfer the sausage to a plate and reserve.
Return the skillet to the stove over medium heat. Add the onion, eggplant, and bell pepper and cook, stirring occasionally, until softened, about 5 minutes. Add the garlic and a little water if needed so th