Preheat your oven to 375°F (190°C).

Bring a large pot of salted water to a boil. Add the lasagna noodles and cook according to the package directions for 8-10 minutes. Drain and rinse under cold water.

In a large skillet, heat a splash of olive oil over medium heat. Sauté the onion for about 3-4 minutes until soft. Stir in the ground beef and cook for 6-8 minutes until browned. Drain excess grease.

Add minced garlic to the skillet and sauté for an additional minute. Pour in marinara sauce, Italian seasoning, and chopped parsley. Stir to combine and let it simmer for 10-15 minutes.

In a mixing bowl, whisk together the egg and ricotta cheese until smooth and creamy.

Start layering in a 9x13-inch baking dish with a thin layer of sauce, then noodles, followed by ricotta mixture, meat sauce, and mozzarella cheese. Repeat layers, ending with sauce and mozzarella.

Cover with aluminum foil and bake for 35 minutes. Remove foil and bake for an additional 10-15 minutes until bubbly and golden.

Let the lasagna rest for about 10 minutes before serving.