Preheat oven to 350 degrees F. Prepare an 8x8-inch casserole dish with nonstick cooking spray.
Ladle a third of the marinara sauce into the bottom of the pan, followed by a third of the frozen ravioli.
Ladle another third of the sauce over the ravioli, and sprinkle half the mozzarella and Parmesan cheese over the sauce.
Repeat with one more layer, cover with aluminum foil and bake for 30 minutes.
Remove the foil and bake for another 15 minutes. Serve immediately or bring to room temperature, cover with plastic wrap and freeze for an easy make-ahead meal. To heat from frozen, cover with aluminum foil and bake at 350 degrees for 45 minutes or until warmed through.