Make the Meat Sauce: In a large pot or Dutch oven, cook the ground beef and sausage over medium heat until browned. Drain off excess fat.
Add the chopped onion and cook until softened, about 5 minutes. Stir in the minced garlic and cook for 1 minute more until fragrant.
Pour in the crushed tomatoes and tomato sauce. Stir in the red wine (if using), basil, oregano, red pepper flakes, salt, and black pepper. Bring to a simmer, then reduce heat and cook for at least 30 minutes, stirring occasionally. The longer it simmers, the better the flavor.
Make the Cheese Filling: In a medium bowl, combine the ricotta cheese, beaten egg, ¼ cup Parmesan cheese, parsley, salt, and pepper. Mix well.
Preheat oven to 375°F (190°C). Grease a 9x13 inch baking dish.
Assemble the Lasagna: Spread a thin layer of meat sauce on the bottom of the prepared baking dish.
Arrange 3-4 lasagna noodles over the sauce, overlapping slightly.
Spread half of the ricotta mixture over the noodles.
Top with about one-third of the remaining meat sauce.
Sprinkle with about one-third of the mozzarella cheese.
Repeat layers: noodles, ricotta, meat sauce, mozzarella. Add a final layer of noodles, the rest of the meat sauce, and the remaining mozzarella and Parmesan cheeses.
Bake for 25-30 minutes, or until bubbly and lightly browned. Let stand for 10-15 minutes before serving.
Notes
For an even richer flavor, you can add a layer of béchamel sauce before the final cheese topping.