Cook quinoa according to directions on package using either water or broth.
Preheat oven to 350 degrees. Place halved bell peppers in a lightly sprayed 9x13” baking dish and set aside.
Heat oil in a large sauté pan on medium-high heat. Add onion and cook until translucent. Add remaining ingredients to the pan, including cooked quinoa and combine. Add additional salsa if preferred.
Generously stuff the peppers with the filling. Place a sheet of aluminum foil over the baking dish and place in preheated oven for 35 minutes.
Remove foil and place baking dish back in oven for an additional 10 minutes.
Serve with your choice of toppings: chopped avocado, cilantro, fresh tomatoes, etc.