Preheat oven to 350°F (177°C). Spray a 9X13-inch baking dish lightly with nonstick cooking spray. Spray a piece (large enough to cover baking dish) of aluminum foil with cooking spray. Place on counter sprayed side up; set aside.
In a mixing bowl, stir together ricotta (1 container), Italian seasoning (2 teaspoons), nutmeg (1/8 teaspoon), and egg (1) until evenly combined; set aside.
Spread 1/2 cup of marinara sauce evenly across the bottom of the prepared baking dish. Arrange one package of ravioli in a layer in a baking dish.
Top ravioli layer with 1/2 cup of marinara sauce.
Sprinkle 1 cup of shredded mozzarella and 1/2 cup Parmesan.
Dollop the ricotta mixture as evenly as possible over the cheese layer then spread it out.
Repeat with another layer of 1/2 cup sauce, ravioli, remaining sauce (it's about 3/4 cup), mozzarella and Parmesan cheese.
Cover the baking dish with prepared foil, and spray side down. Place the baking dish on a rimmed baking sheet, then bake in preheated oven for 30 minutes. Remove the baking dish from the oven and remove and discard the foil. Continue to bake for another 14-20 minutes until the casserole is heated through, bubbly, and the cheese is melted. If you want the top browned more, place it under the broiler with a watchful eye for a couple of minutes.
Remove from oven and allow casserole to cool for 10 minutes. Top with parsley or basil.