Combine "beef", onion, salsa, seasoning mix and egg in a large bowl. Add rice and mix well.
Cut "lids" off of peppers. Spread tomatoes on the bottom of a 13 X 9 inch baking dish.
The liquid from the tomatoes will reduce during cooking. This also helps make the peppers softer.
Place peppers on top of the tomatoes. Spoon beef mixture into peppers, mounding as necessary. Bake in preheated 375°F oven for 40-45 minutes or until peppers are soft.
Top each with extra salsa. Cover each pepper with cheese and return to oven, under the broiler, until the cheese melts.
