Start by making the sauce if you don't have any already made. Preheat your oven to 450°F. Spray two sheet pans with olive oil. While the sauce simmers, slice the eggplant into 1/4 inch thick slices. Transfer the sliced eggplant to the prepared pans, allowing for slight overlaps. Season with kosher salt. Bake the eggplant for 20 minutes, turning halfway through. Meanwhile, in a medium bowl, combine ricotta, a large egg, chopped parsley, and 1/4 cup of grated Pecorino Romano. Put 1/2 cup of sauce on the bottom of a 9x12 baking dish. Add 1/3 of baked eggplant to cover the bottom of the dish. Top with 1/3 of the ricotta mixture, 3/4 cup of mozzarella cheese, and 3/4 cup of sauce. Add another layer of eggplant and repeat the layering process with the remaining ricotta, mozzarella, and sauce two more times. Save the last layer of mozzarella for topping. Finish with the remaining sauce and cheese.
