Preheat the oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish with olive oil.
Spread a thin layer of marinara sauce across the bottom of the dish.
Arrange a layer of frozen ravioli over the sauce, keeping them in a single, even layer.
Spoon more marinara sauce over the ravioli, covering them generously.
Sprinkle mozzarella and a bit of Parmesan over the sauce.
Repeat the layers: ravioli → sauce → cheeses. Add a few dollops of ricotta between layers if using.
Finish with a generous top layer of mozzarella and Parmesan. Sprinkle with Italian seasoning if desired.
Cover with foil and bake for 30 minutes.
Uncover and bake an additional 10–15 minutes, or until the top is golden and bubbling.
Let rest for 10 minutes before slicing and serving. Garnish with fresh basil or parsley.