In a large skillet over medium heat, add the ground beef or Italian sausage along with the diced onion. Cook for about 5–7 minutes until browned and translucent.

Stir in the minced garlic and sauté for an additional minute. Pour in the marinara sauce and sprinkle Italian seasoning. Let simmer for 10 minutes.

In a bowl, combine ricotta cheese, the egg, half of the grated Parmesan, and a pinch of salt and black pepper. Mix until creamy.

Spread a layer of meat sauce in a baking dish, then layer the no-boil noodles, ricotta mixture, and mozzarella. Repeat layers, finishing with sauce and cheese.

Cover with aluminum foil and bake in a preheated oven at 375°F for 25 minutes.

Remove foil and bake for an additional 20-25 minutes until cheese is bubbly and golden.

Let the lasagna rest for 10-15 minutes before serving.