Preheat the Oven: Preheat your oven to 375°F (190°C).
Prepare the Sauce: Heat olive oil in a large pan over medium heat. Add chopped onions and minced garlic, cooking until soft. Add ground beef (or sausage) and cook until browned. Stir in the tomato sauce, Italian seasoning, salt, and pepper. Let it simmer for 15-20 minutes to develop the flavors.
Prepare the Ricotta Mixture: In a medium bowl, combine ricotta cheese, 1 cup of mozzarella cheese, Parmesan cheese, and the egg. Mix well and set aside.
Boil the Noodles: Cook the Ronzoni lasagna noodles according to the package directions. Drain the noodles and set them aside.
Assemble the Lasagna: Spread a thin layer of the meat sauce on the bottom of a 9x13-inch baking dish. Place a layer of lasagna noodles over the sauce. Spread half of the ricotta mixture over the noodles, followed by a generous layer of meat sauce. Repeat the layering process, ending with a layer of meat sauce and a sprinkle of the remaining mozzarella and Parmesan cheese on top.
Bake the Lasagna: Cover the dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the top is bubbly and golden brown.
Cool and Serve: Let the lasagna rest for 10-15 minutes before cutting into it. Garnish with fresh basil if desired.