Heat olive oil in a large skillet over medium heat. Cook ground beef and Italian sausage until browned, about 5-7 minutes. Stir in diced onion and cook until softened, about 3-4 minutes. Add minced garlic.

Pour in crushed tomatoes, tomato sauce, and tomato paste. Season with salt, pepper, basil, oregano, and optional sugar. Simmer on low for 25-30 minutes until thickened.

In a pot, bring salted water to a rolling boil. Add lasagna noodles and cook according to package instructions until al dente, about 8-10 minutes. Drain and lay noodles flat on parchment paper.

In a medium bowl, combine ricotta cheese, beaten egg, grated Parmesan, shredded mozzarella, and a pinch of salt and pepper. Mix until smooth and creamy.

Preheat the oven to 375°F (190°C). In a baking dish, spread a thin layer of meat sauce on the bottom. Lay down lasagna noodles, spoon cheese mixture, and layer meat sauce and mozzarella. Repeat layers and finish with noodles, meat sauce, and mozzarella on top.

Cover with aluminum foil and bake for 35 minutes. Remove foil and bake for another 15-20 minutes until bubbly and golden brown. Let rest for 15 minutes before slicing.