Preheat the oven to 400 degrees . In a pot of boiling, salted water, cook the pasta until al dente; drain.
Meanwhile, on a foil-lined baking sheet, rub the eggplant with 3 tbsp. EVOO; season with salt and pepper. Broil, turning once, until browned, about 7 minutes.
In a saucepan, heat the remaining 1 tbsp. EVOO over medium heat. Add the garlic and cook, stirring, for about 3 minutes. Add the marinara.
Spread one-quarter of the sauce on the bottom of an 8-by-10-inch casserole dish. Layer with half of the pasta. Top with one-third each of the mozzarella and parmesan; repeat the layering, starting with more sauce. Layer on the eggplant and press firmly to pack down. Dollop the remaining sauce on top; sprinkle with the remaining mozzarella and parmesan. Bake until the cheese is browned and the sauce is bubbling, about 30 minutes.