Preheat oven:
Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish.
Cook the ravioli:
Cook the ravioli according to the package instructions, but slightly undercook them (by about 1-2 minutes) since they will cook further in the oven. Drain and set aside.
Prepare the creamy cheese mixture:
In a medium bowl, combine ricotta cheese, sour cream, cream cheese, garlic powder, Italian seasoning, and 1 cup of shredded mozzarella cheese. Mix until smooth and well combined.
Assemble the casserole:
Spread a thin layer of marinara sauce on the bottom of the prepared baking dish.
Add half of the cooked ravioli in a single layer over the sauce.
Spread half of the creamy cheese mixture over the ravioli.
Drizzle half of the marinara sauce over the cheese layer.
Repeat the layers with the remaining ravioli, creamy cheese mixture, and marinara sauce.
Top with cheese:
Sprinkle the remaining 1 cup of mozzarella cheese and the Parmesan cheese evenly over the top layer.
Bake the casserole:
Cover the dish with aluminum foil (to prevent the cheese from browning too quickly) and bake for 20 minutes.
Remove the foil and bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Garnish and serve:
Let the casserole rest for 5-10 minutes before serving. Garnish with fresh basil or parsley for a pop of color and added flavor.