Prepare a pot of water over medium heat.
Prepare the peppers by washing and cutting off tops of the peppers and removing the seeds.
Place peppers in the water and blanch the peppers about 3-4 minutes.
Place blanched peppers in a baking pan, opening side up and set aside.
Preheat oven to 350 degrees f.
In a large skillet, cook the hamburger and onion over medium heat until hamburger is brown.
Drain thoroughly and break up hamburger.
Add rice, tomato sauce, salt, sugar, garlic, and black pepper to mixture and combine.
Stuff each pepper to nearly the top with hamburger mixture. Top with cheese.
Bake for 20 minutes in preheated oven.