Preheat oven to 350.
Cook the rice as directed.
Blanch the halved and seeded peppers by placing peppers into boiling water for 2-3 minutes and then place them in ice water for 2-3 minutes. Remove peppers from water and set aside. If you skip this blanching step, the peppers can become mushy.
Place the peppers in a 9x13 baking dish with the hallow insides facing upward so that you can stuff them.
Brown ground beef in a skillet, and drain grease (if any). Stir in rice, 1 can tomato sauce, Worcestershire sauce, Parmesan cheese, garlic power, onion powder, and salt and pepper. Let simmer for about 10 minutes, remove from heat.
Spoon mixture into each of the peppers, and poor remaining tomato sauce over stuffed peppers.
Cover pan with aluminum foil, and bake for 20 minutes. Uncover and bake 10 more minutes, or until peppers are tender.
If desired, sprinkle mozzarella cheese over the top of each pepper, and cook until cheese is fully melted.