1. Preheat your oven to 375°F (190°C). Line a baking dish with parchment paper to prevent sticking.
2. Slice the tops off the bell peppers and remove the seeds and membranes. Rub the insides with a tablespoon of olive oil, then season with salt and pepper.
3. In a large bowl, combine the shredded chicken, buffalo sauce, half of the mozzarella cheese, quinoa or rice if using, green onions, and a pinch of salt and pepper. Mix until everything is well coated.
4. Stuff each pepper with the chicken mixture, pressing down gently to ensure they’re filled to the top.
5. Top each stuffed pepper with the remaining mozzarella cheese and a sprinkle of blue cheese.
6. Place the peppers upright in the prepared baking dish. Drizzle the remaining olive oil over the tops.
7. Bake for 25-30 minutes, or until the peppers are tender and the cheese is bubbly and golden.
8. Remove from the oven and let them cool for a few minutes. Garnish with fresh parsley before serving.

Using a mix of colored peppers not only makes this dish visually appealing but also adds a variety of subtle sweetness, enhancing the overall taste.