Begin by preheating your oven to 375°F (190°C) to ensure it is ready for baking.
In a large pot, bring salted water to a boil. Carefully add the lasagna noodles and cook according to package instructions until they are al dente. Once cooked, drain the noodles and lay them on a baking sheet in a single layer to prevent them from sticking together.
Meanwhile, heat the olive oil in a large skillet over medium heat. Add the chopped onion and sauté for about 3-4 minutes until they become translucent and soft. Then, add the minced garlic, cooking for an additional minute to release its fragrant aroma.
Next, add the ground beef or turkey to the skillet. Cook, breaking it apart with a spatula, until it is fully browned and no longer pink. Drain any excess fat to keep the filling lighter.
Pour in the marinara sauce and stir in the dried oregano, fresh basil, salt, and pepper. Allow the mixture to simmer for 5-10 minutes, letting the flavors blend beautifully.
In a medium bowl, mix together the ricotta cheese, egg, and a pinch of salt and pepper until well combined and smooth.
For assembling, start by spreading a thin layer of the meat sauce at the bottom of a 9x13 inch baking dish. Place 4 lasagna noodles on top of the sauce, ensuring they don't overlap.
Next, evenly spread half of the ricotta mixture over the noodles, followed by a generous layer of meat sauce and a sprinkle of mozzarella cheese. Repeat this layering process (noodles, ricotta, meat sauce, mozzarella) until you've used all the ingredients.
For the topmost layer, place the last 4 noodles, finish with the remaining meat sauce, sprinkle over the rest of the mozzarella cheese, and finally, add the grated Parmesan cheese on top for that extra cheesy finish.
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes. Then, remove the foil and bake for another 15-20 minutes, or until the cheese is melted, bubbly, and lightly golden.
Allow the lasagna to cool for about 10-15 minutes before slicing. This resting time will help the lasagna hold its shape upon serving.
Notes
For an appealing presentation, serve the lasagna in square portions topped with a fresh sprinkle of basil. Accompany with a warm side of garlic bread for a complete and inviting meal.