Preheat your oven to 375°F (190°C).
In a large pot, bring water to a boil. Cook the lasagna noodles according to package instructions until al dente. Drain and set aside.
In a skillet, heat a drizzle of olive oil over medium heat. Add chopped onion and minced garlic, sauté until translucent.
Add ground beef and Italian sausage to the skillet, cook until browned. Drain excess fat.
Stir in crushed tomatoes, basil, oregano, salt, and pepper into the meat mixture. Simmer for about 10 minutes to blend flavors.
In a mixing bowl, combine ricotta cheese, egg, and a pinch of salt and pepper. Mix well.
In the baking dish, spread a thin layer of the meat sauce on the bottom. Layer 3 lasagna noodles on top, then add half of the ricotta mixture, a third of the mozzarella cheese, and a layer of meat sauce. Repeat the layers once more.
For the final layer, place the last 3 noodles on top, spread remaining meat sauce, and sprinkle with the remaining mozzarella and Parmesan cheese.
Cover the baking dish with foil and bake for 30 minutes. Remove the foil and bake for an additional 15 minutes, or until cheese is bubbly and golden.
Let the lasagna rest for 15 minutes before slicing. Serve warm.