Reduce the oven temperature to 375 degrees.
While the eggplant is baking, place the ricotta, egg, Parmesan, parsley, ½ teaspoon salt, and ½ teaspoon pepper in a bowl and mix thoroughly.
Pour a thin layer of marinara sauce to cover the bottom of a baking dish.
Depending on how many servings you are making, place 8 to 10 of the larger eggplant slices in the dish.
Place a slice of mozzarella on each piece of eggplant. Slice the mozzarella, so you have two slices per serving.
Spoon a scoop of the ricotta mixture onto each slice.
Lay another slice of eggplant on each serving.
Pour a spoonful or two of sauce over each stack.
Add another slice of mozzarella and a dollop of ricotta to each serving.
Place the dish in the oven and bake for 15 to 20 minutes.
Turn the broiler on for a few minutes to brown the top a bit, then remove from the oven.
Garnish each serving with fresh basil and extra marinara sauce.
Plating tip: Ladle some sauce onto the plate, place a stack of eggplant on top, and garnish with fresh basil.