01 - Preheat oven to 375°F.
02 - Cut bell peppers in half lengthwise and remove seeds and membranes. Place them cut side up in a lightly oiled baking dish.
03 - Drizzle the peppers with 1 tablespoon olive oil and season lightly with salt and pepper.
04 - In a large bowl, combine ricotta, Parmesan, mozzarella, egg, garlic, basil, parsley, oregano, lemon zest, salt, black pepper, and red pepper flakes. Mix until smooth.
05 - Spoon the ricotta mixture evenly into each pepper half, mounding slightly.
06 - Drizzle remaining 1 tablespoon olive oil over the stuffed peppers. Sprinkle with extra Parmesan if desired.
07 - Cover the baking dish with foil and bake for 25 minutes.
08 - Remove foil and bake an additional 10 minutes, or until peppers are tender and tops are golden.
09 - Garnish with fresh basil before serving.