Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain.
In a large skillet over medium heat, brown the ground beef. Add the tomatoes with juice, salt and sugar and simmer for 15 minutes.
In a separate medium bowl, combine the sour cream, cream cheese and onion and mix well. In a 9x13 inch baking dish, place half of the egg noodles, then all of the meat mixture, then the cream mixture. Top with the remaining noodles and sprinkle with the cheese.
Bake at 350 degrees F (175 degrees C) for 25 minutes.
