Bring a large pot of salted water to a rolling boil. Add the lasagna noodles and cook according to the package instructions, typically about 8–10 minutes, until al dente. Drain and set aside.

In a skillet, heat olive oil over medium heat. Add ground beef and cook until browned, about 5–7 minutes. Drain excess fat and stir in marinara sauce, diced tomatoes, and Italian seasoning. Simmer for 10 minutes, then season with salt and pepper.

In a mixing bowl, combine ricotta cheese, egg, and grated Parmesan cheese. Mix until smooth and creamy.

Preheat the oven to 375°F (190°C). Begin layering in a baking dish with a thin layer of meat sauce, followed by noodles, ricotta mixture, mozzarella, and more meat sauce. Repeat layers and finish with noodles and meat sauce topping.

Cover with foil and bake for 25 minutes, then remove foil and bake for an additional 20 minutes until golden brown and bubbly.

Allow lasagna to rest for at least 10 minutes before slicing. Garnish with chopped basil or parsley before serving.