- Preheat oven to 375°F. 
- In a medium saucepan, bring the vegetable stock and water to a boil. Add the quinoa or rice and reduce to a simmer. If preparing quinoa, let it cook for 20-30 minutes or until tender. If preparing rice, let it cook for 15-20 minutes or until tender. Set aside. 
- In a large bowl, combine the cooked quinoa or rice, lentils, spinach, canned corn, cumin, oregano, garlic powder and red pepper flakes. Mix well. 
- Drizzle the mixture with olive oil and add salt and pepper to taste. Mix well. 
- Wash the peppers, cut them in half lengthwise and remove the seeds and inside edges.  
- Scoop the stuffing mixture into the pepper, pressing it down with every spoonful. Continue until the mixture is heaping over the edges. Sprinkle the tops with grated cheese. 
- Place the stuffed peppers in a 9x13 Pyrex dish and bake for 25-30 minutes or until the cheese is starting to brown and the peppers are cooked through. 
- Allow the peppers to cool for 10 minutes. Add your desired toppings, pair with a side of greens and/or grains and enjoy!