01 - Preheat the oven to 375°F (190°C). Lightly grease a baking dish with 1 tablespoon olive oil.
02 - Arrange the pepper halves, cut side up, in the baking dish. Drizzle with remaining olive oil and season lightly with salt and pepper.
03 - In a large bowl, combine ricotta, Parmesan, spinach, parsley, basil, chives, garlic, lemon zest, salt, pepper, and egg. Mix until smooth and well-blended.
04 - Spoon the ricotta filling evenly into each pepper half, pressing gently to fill.
05 - Sprinkle with mozzarella cheese, if using.
06 - Cover the dish with foil and bake for 25 minutes.
07 - Remove the foil and bake for an additional 10 minutes, or until the peppers are tender and the filling is golden.
08 - Let cool for 5 minutes before serving.