Pre-heat oven to 325 degrees. Place the 1 cup of Quinoa in a sauce pan with 2 cups of broth and bring to a boil , reduce & simmer , cover & cook until all liquid is absorbed (10-15 minutes) When done it will be it will appear translucent & soft. While cooking Quinoa steam bell peppers in microwave until soft but not limp. In a large skillet saute the onions & mushrooms in the olive oil. Add the diced tomatoes & seasonings reserving tomato juice. After stirring add either tomato sauce or salsa, cook over medium heat for about 10 minutes. While cooking mixture, cut peppers lengthwise & remove seeds & place in pre-sprayed baking pan. Next fold in Quinoa & mozzarella cheese into mixture. Take mixture & fill peppers. Some will be left over, use it around the peppers. Use tomato juice reserved to pour on & around the peppers. Bake for 30-35 minutes & serve hot!