In a large skillet over medium heat, sauté diced onion and minced garlic in olive oil until softened, about 5 minutes. Add the Italian sausage and ground beef, cooking until browned and fully cooked, approximately 8-10 minutes.

Stir in the crushed tomatoes, tomato sauce, and tomato paste with the water, followed by the dried basil, Italian seasoning, fennel seed, granulated sugar, and season with salt and pepper. Mix well and bring to a gentle simmer.

While the sauce simmers, prepare the ricotta layer. In a medium bowl, combine the ricotta cheese with chopped fresh parsley, the whole egg, and a pinch of salt. Mix until smooth and creamy.

Bring a large pot of salted water to a boil. Carefully add the lasagna sheets and cook according to package instructions until al dente, typically 8-10 minutes. Drain the pasta and rinse briefly under cold water.

In a deep baking dish, spread a layer of the meat sauce on the bottom. Place a layer of lasagna sheets over the sauce, followed by half of the ricotta mixture and a generous sprinkle of shredded mozzarella.

Cover the assembled Maggiano’s Lasagna tightly with aluminum foil and bake in a preheated oven at 375°F for 25 minutes. After 25 minutes, carefully remove the foil and bake for an additional 25 minutes.

Once baked to a glorious golden brown, remove the lasagna from the oven and let it cool for at least 15 minutes. After cooling, cut into squares and serve warm.