In a large skillet, heat the olive oil over medium heat. Add the chopped onion and minced garlic. Sauté until the onion is translucent and fragrant, about 3-5 minutes.

Increase the heat and add the lean ground beef and mild Italian sausage. Cook until browned, about 6-8 minutes. Drain excess fat.

Stir in the canned tomato sauce, oregano, basil, salt, and pepper. Simmer for about 15 minutes on low heat.

In a mixing bowl, combine ricotta cheese with eggs, salt, pepper, and half of the grated Parmesan cheese. Mix until smooth.

In a baking dish, layer half of the meat sauce, three lasagna noodles, half of the ricotta mixture, and half of the mozzarella cheese. Repeat for a total of two layers.

For the final layer, spread remaining meat sauce on top, sprinkle with mozzarella cheese, and add the rest of the Parmesan cheese. Cover with foil.

Bake covered at 375°F (190°C) for 25 minutes, then remove foil and bake for an additional 15 minutes until bubbly and golden brown.