In a large skillet, heat olive oil over medium heat. Add ground beef and Italian sausage, cooking until browned, about 5-7 minutes. Stir in diced onion and sauté until softened, about 4 minutes. Add minced garlic, then mix in crushed tomatoes, tomato sauce, and tomato paste. Season with salt, pepper, dried basil, and oregano, simmering for 25-30 minutes until thickened.

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

In a mixing bowl, combine ricotta cheese, beaten egg, grated Parmesan cheese, and shredded mozzarella. Season with salt, pepper, and chopped parsley. Stir until creamy and well-blended.

Preheat the oven to 375°F (190°C). In a baking dish, layer meat sauce, noodles, and half of the cheese mixture. Repeat layers, topping with more meat sauce and mozzarella.

Cover the lasagna with aluminum foil and bake for 35 minutes. Remove foil and bake for an additional 15-20 minutes until cheese is bubbly and golden brown. Let rest for 15 minutes before slicing.

Slice the lasagna into squares and serve hot, preferably with a fresh salad and crusty garlic bread.