Grease a 9x13 baking dish with non-stick spray. Pour half of the marinara sauce into the bottom of the pan and spread evenly.
Place the pierogis next to each other in the dish and pour the remaining marinara sauce over the top. Pour the Alfredo sauce over everything and spread evenly. Sprinkle the top with Parmesan cheese. Cover with aluminum foil.
Bake for 40 minutes. Remove the foil and bake for an additional 15 minutes. Enjoy!