Step 1

Preheat oven to 400° F. Spray a 9-inch by 13-inch baking dish (or two 8-inch dishes) with cooking spray.

Step 2

Pour a very thin layer of marinara sauce into the prepared baking dish to cover bottom (about ½ cup).

Step 3

Arrange half of the frozen ravioli in a single layer over the sauce.

Step 4

Top with half of the remaining marinara sauce and half of the mozzarella cheese.

Step 5

Repeat layers once, starting with ravioli. Sprinkle Parmesan cheese on top.

Step 6

Cover with aluminum foil and bake for 20 minutes. Remove foil and bake, uncovered, for 20-25 more minutes or until bubbly and hot in center. Let stand 10 minutes before serving.