Preheat your oven to 375°F (190°C) and heat a large skillet over medium heat. Brown 1 pound of ground beef for about 6-8 minutes until fully cooked and no longer pink. Drain any excess fat, then stir in 24 ounces of marinara sauce and allow to simmer for 10 minutes.

In a large pot, bring salted water to a boil and cook 9 lasagna noodles according to package instructions, usually around 8-10 minutes. Drain and lay them flat on a clean kitchen towel.

Combine 15 ounces of ricotta cheese, 1 egg, 1 teaspoon of Italian seasoning, and a pinch of salt and pepper in a mixing bowl. Blend until smooth and creamy.

In a 9x13-inch baking dish, spread a thin layer of the meat sauce on the bottom. Lay down 3 noodles, followed by half of the ricotta mixture, then 1 cup shredded mozzarella. Repeat layering, finishing with remaining meat sauce and topped with 1 cup grated Parmesan.

Cover with aluminum foil and bake for 25 minutes. Remove foil and bake an additional 15 minutes until bubbly and golden brown.

Let the lasagna stand for about 10 minutes before slicing to allow the layers to set.