Preheat oven to 375°F (190°C).
Brown the ground beef in a skillet over medium-high heat until fully cooked; drain excess fat.
Stir the marinara sauce into the beef and simmer for 5 minutes.
In a medium bowl, whisk the egg and mix with ricotta cheese and dried oregano.
Spread 1 cup of the meat sauce in the bottom of a 9x13 inch baking dish.
Place 3 no-boil noodles over the sauce.
Spread half of the ricotta mixture over the noodles, followed by 1 cup of meat sauce and 1/2 cup of mozzarella.
Repeat the layer with 3 noodles, the remaining ricotta mixture, 1 cup of sauce, and 1/2 cup mozzarella.
Add the final 3 noodles, remaining sauce, remaining mozzarella, and the parmesan cheese.
Cover the dish tightly with aluminum foil and bake for 30 minutes.
Remove the foil and bake for an additional 15 minutes until the cheese is golden and bubbly.
Let stand for 10 minutes before slicing to allow the layers to set.