Preheat oven to 375 degrees. Line a baking pan or baking dish with foil. Place halved bell peppers on pan and set aside until ready to fill.*
In a large, deep skillet, heat about 1 tablespoon olive oil over medium-high heat. Add diced onion and sauté until softened and fragrant, about 4-5 minutes. Add turkey meat (or desired protein) to skillet and sauté until no longer pink.
Toss in carrots, broccoli and zucchini and cook for about 4-5 minutes until just starting to soften. Add quinoa and stir to combine.
Meanwhile, in a small bowl or measuring cup, whisk together soy sauce, water, sesame oil, sriracha, ginger, garlic and cornstarch {try to make sure there are no cornstarch lumps if possible}. Add to meat and vegetable mixture and stir until everything is well-coated and sauce is slightly thickened. Remove from heat.
Spoon filling evenly among bell pepper halves.
Place filled bell peppers in a baking dish with 3 tablespoons water (or broth) poured into the bottom. Cover with foil and bake for about 15-20 minutes or until the peppers become slightly tender.
Serve hot or warm.