Heat the olive oil in a large skillet over medium heat. Add the chopped onion and minced garlic, stirring until the onion is translucent, about 3–4 minutes.

Add the ground beef to the skillet, cooking until browned. Drain excess fat.

Stir in crushed tomatoes, tomato paste, oregano, basil, salt, and pepper. Simmer for 15–20 minutes.

In a medium bowl, combine ricotta cheese, shredded mozzarella, grated Parmesan, egg, salt, pepper, and parsley. Mix until well combined.

Preheat your oven to 375°F (190°C).

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

Lay down a layer of lasagna noodles over the sauce.

Spoon a layer of the cheesy mixture over the noodles.

Repeat layers of beef sauce, noodles, and cheese mixture until all ingredients are used, finishing with a layer of beef sauce.

Sprinkle remaining shredded mozzarella and extra Parmesan on top.

Cover with aluminum foil and bake for 25 minutes, then uncover and bake for an additional 20–25 minutes.

Let the lasagna cool for 10–15 minutes before slicing.

Serve and enjoy!