Lightly spray baking dish with nonstick cooking spray.Spoon a small amount of marinara sauce into the bottom of a baking dish or dutch oven.
Add a single layer of ravioli (about ⅓ of the bag).
Sprinkle with a handful of cheese.
Add a handful of spinach.
Pour half of the remaining sauce on top and spread with a spoon.
Add another layer of ravioli (⅓ of the bag).
Add a second layer of cheese.
Add a second handful of spinach.
Add remaining sauce over spinach and spread with a spoon.
Add remaining ravioli and sprinkle with mozzarella cheese.
Sprinkle with parmesan cheese.
Cover with foil or a lid and bake for 30 minutes.
Uncover and bake an additional 15-20 minutes. Ravioli bake should be bubbly.
If you'd like to brown the cheese on top you can turn on the broiler for a minute or two (watch carefully to prevent burning). Serve with garlic bread and salad!
Video
Notes
The ravioli that I used was fresh (found in the refrigerator/fridge section). If using frozen ravioli you may need to adjust the baking time, adding 10-15 minutes or so.If using a 9x13 baking dish you'll have 2 layers of ravioli, if using a Dutch oven you'll most likely have 3 layers.For more of a lasagna flavor, consider adding some ricotta cheese to the layers.