Preheat oven to 350°.
Parboil rice about 5 minutes; drain.
Cut peppers in half vertically (top to bottom); remove seeds; parboil 5 minutes; drain.
Mix meat, egg, rice, seasonings, cheese and grated onion together. Place mixture into pepper halves and place in baking container with sauce.
Mix sauce ingredients together.
Place about half of sauce into baking dish.
Arrange peppers in dish. Cover with rest of sauce.
Sprinkle with more cheese and a little more oregano.
Bake in 350° oven 1 1/2 hours; remove cover about 15 minutes before end of cooking time-if you wish meat mixture to be browned.