Preheat the oven to 375°F (190°C).

Bring a large pot of salted water to a boil and cook the lasagna noodles for 8–10 minutes until al dente, then drain and set aside.

In a skillet over medium heat, brown the ground beef and Italian sausage for 5–7 minutes, breaking up the meat until no pink remains; drain excess fat.

Add the marinara sauce to the cooked meat and simmer for 10 minutes to meld flavors, stirring occasionally.

In a mixing bowl, combine the ricotta cheese, egg, dried oregano, salt, and pepper until smooth.

Spread a thin layer of the meat sauce on the bottom of the 9x13 inch baking dish.

Arrange a single layer of cooked lasagna noodles over the sauce, ensuring they slightly overlap.

Spread half of the ricotta mixture over the noodles, followed by one-third of the meat sauce; repeat layers once more and finish with remaining noodles and sauce.

Sprinkle the shredded mozzarella and grated Parmesan evenly over the top layer.

Cover the dish tightly with foil and bake in the preheated oven for 25 minutes.

Remove the foil and bake for an additional 10 minutes, or until the cheese is golden and bubbly.

Let the lasagna rest for 15 minutes before slicing to ensure clean servings.