Bring a large pot full of water to a boil. Add peppers and boil for 3 minutes. Set aside in a sprayed 9 x 13 dish to cool and dry. Preheat oven to 350 degrees. Brown the ground beef, onion and garlic powder. Drain. Add back to the skillet and add tomatoes. Cook until tomatoes are heated through. Remove from heat and add the 4 oz of cheese. Salt and pepper to taste. Fill the peppers with the meat mixture. Top with remaining cheese and bake at 350 degrees for 20-25 minutes.