Preheat your oven to 375°F (190°C) and cook the lasagna noodles according to package directions until al dente.

In a large bowl, combine ricotta cheese, grated Parmesan, egg, chopped fresh parsley, salt, and pepper, mixing well to create the cheese filling.

Brown the ground beef and chopped onion in a large skillet; drain any excess fat, then stir in minced garlic and cook for another minute.

Add crushed tomatoes, tomato paste, Italian seasoning, sugar, salt, and pepper to the skillet with the meat, bringing the sauce to a simmer and cooking for at least 15 minutes.

Spread a thin layer of meat sauce in the bottom of a 9x13 inch baking dish, then arrange a layer of cooked lasagna noodles over the sauce.

Evenly spread half of the ricotta cheese mixture over the noodles, followed by a layer of meat sauce and then a sprinkling of shredded mozzarella cheese.

Repeat the layers, ending with noodles, the remaining meat sauce, and a final generous layer of mozzarella cheese.

Cover the baking dish with aluminum foil and bake for 25 minutes, then remove the foil and continue baking for an additional 20-25 minutes, or until the cheese is bubbly and lightly browned.

Allow the lasagna to cool for 10-15 minutes before slicing and serving to allow it to set.