In a large skillet over medium heat, combine the ground beef and Italian sausage, cooking until browned, about 7-10 minutes. Add finely chopped onions and minced garlic, sautéing until softened, approximately 3-4 minutes. Stir in crushed tomatoes, tomato paste, tomato sauce, water, sugar, and dried basil. Allow the mixture to simmer for 30 minutes.

In a mixing bowl, combine the ricotta cheese, egg, a pinch of salt, pepper, and fresh parsley. Stir until the mixture is smooth and creamy.

In a large pot of salted water, bring to a boil. Add the lasagna noodles and cook until al dente, about 8-10 minutes. Drain and rinse with cold water.

In a greased 9x13-inch baking dish, spread a layer of meat sauce at the bottom. Place a layer of lasagna noodles on top, followed by a layer of ricotta mixture and sprinkle mozzarella cheese. Repeat layers, finishing with meat sauce and topping with mozzarella.

Preheat oven to 375°F (190°C). Cover lasagna with foil and bake for 25-30 minutes. Remove foil and bake for an additional 10-15 minutes until cheese is melted and golden.

Allow lasagna to cool for about 10 minutes before slicing and serve.