Bring a large pot of salted water to a boil. Core the cabbage and carefully peel off 12-14 large leaves. Blanch 3-4 leaves at a time for 2-3 minutes until pliable and bright green. Transfer to an ice bath, then drain on paper towels. Pat completely dry - wet leaves make watery lasagna.

Heat a large skillet over medium-high heat. Add beef and sausage, breaking into small pieces. Cook until browned and no pink remains, about 8 minutes. Drain excess fat, leaving about 1 tablespoon in the pan.

Add onion to the skillet and cook until softened, 4-5 minutes. Stir in garlic and cook 30 seconds until fragrant. Add tomato paste and cook 1 minute, stirring constantly. Pour in crushed tomatoes, oregano, red pepper flakes, and 1/2 teaspoon salt. Simmer 15 minutes until slightly thickened. Taste and adjust seasoning.

In a medium bowl, combine ricotta, 1 cup mozzarella, Parmesan, egg, and chopped basil. Stir until well blended. Season lightly with salt and pepper.

Preheat oven to 375F. Spread 1 cup meat sauce in the bottom of a 9x13 baking dish. Arrange 4 cabbage leaves to cover, overlapping as needed. Spread half the ricotta mixture, then 1.5 cups sauce. Repeat with 4 more cabbage leaves, remaining ricotta, and 1.5 cups sauce. Top with final 4-6 cabbage leaves, remaining sauce, and 1 cup mozzarella.

Cover tightly with foil and bake 30 minutes. Remove foil and bake 15-20 minutes more until cheese is golden and edges are bubbling. Let rest 15 minutes before slicing - this sets the layers so they hold together when you serve.

Sprinkle with fresh basil and extra Parmesan. Serve warm with a simple green salad and crusty bread if desired.