Preheat your oven to 375°F (190°C).
Cook the lasagna noodles according to package instructions until al dente.
In a bowl, mix ricotta cheese, egg, oregano, salt, and pepper until well combined.
Spread a layer of marinara sauce on the bottom of a greased baking dish.
Layer 3 noodles over the sauce, followed by half of the ricotta mixture.
Add a layer of mozzarella cheese on top of the ricotta.
Repeat the layering process: sauce, noodles, ricotta, and mozzarella.
Top with the remaining noodles, marinara sauce, and sprinkle Parmesan cheese over the top.
Cover with foil and bake for 20 minutes.
Remove foil and bake for an additional 10 minutes until cheese is bubbly and golden.