Cut tops off peppers and remove seeds. Rinse and drain. Place peppers in a pot and cover with water. Cook for 3 minutes after water comes to a boil. Remove peppers to drain on a paper towel.

Filling: Place ground beef and onion in a skillet on medium heat. Cook until the meat is no longer pink. Remove from heat and drain on paper towel. Wipe skillet of excess fat, then return meat to the pan. Add 1/2 can tomato sauce, cooked rice, salt, and pepper. Stir on low heat until ingredients are well mixed. Remove from heat.

Place the cooked/drained peppers in an ungreased 2-qt baking dish. Spoon the meat filling into the two peppers. Pour remaining tomato sauce over the filled peppers.

Cover and bake at 350 degrees for 30 minutes, or until peppers are tender.