01 - Set oven temperature to 375°F (190°C).
02 - Heat olive oil in a large skillet over medium heat. Add onion and cook for 3 minutes until softened. Add garlic and cook an additional minute.
03 - Add ground beef to skillet, breaking apart with a spoon, and cook until fully browned. Drain excess fat if necessary.
04 - Stir in marinara sauce, tomato paste, dried oregano, dried basil, salt, and black pepper. Simmer for 10 minutes, stirring occasionally. Remove from heat.
05 - Combine ricotta cheese, egg, grated Parmesan, parsley, salt, and black pepper in a mixing bowl. Mix until smooth and evenly blended.
06 - Spread 1 cup of meat sauce evenly in the bottom of a 9x13-inch baking dish.
07 - Arrange 3 lasagna noodles over the sauce. Spread one-third of the ricotta mixture over noodles, top with 1 cup of meat sauce, and sprinkle with one-third of the mozzarella cheese.
08 - Repeat layering process twice: noodles, ricotta mixture, meat sauce, mozzarella. Finish with remaining mozzarella cheese on top layer.
09 - Cover baking dish with lightly greased aluminum foil. Bake covered for 25 minutes.
10 - Remove foil and bake for an additional 15 to 20 minutes until cheese is golden and bubbling.
11 - Allow dish to rest for 10 to 15 minutes prior to slicing and serving to ensure clean portions.