Heat oven to 400 degrees F. Rub the pepper halves inside and out with olive oil and arrange cut-side up in a 9x13 inch baking dish. Roast for 15 minutes until just starting to soften but still holding their shape.

While peppers roast, warm a large skillet over medium-high heat. Add ground beef, breaking it up with a wooden spoon. Cook 6-8 minutes until browned and no pink remains. Drain excess fat if needed.

Stir in Italian seasoning, garlic, and marinara. Reduce heat to medium-low and simmer 5 minutes until slightly thickened. Remove from heat.

In a small bowl, combine ricotta, 1/4 cup Parmesan, egg, and half the basil. Stir until smooth.

Spoon a thin layer of meat sauce into each pepper half. Add a generous dollop of ricotta mixture, then more meat sauce. Top with mozzarella and remaining Parmesan.

Return to oven and bake 18-20 minutes until cheese is melted and bubbling with golden spots. Let rest 5 minutes, then sprinkle with remaining basil before serving.