In a large pot with boiling salted water cook pasta until al dente. Drain.
In a large skillet saute one pound of ground beef. Stir in one can of the tomato sauce and cook together slightly. Add the additional 2 cans of tomato sauce and 1/3 cup sour cream; heat gently.
To assemble, in a greased 9x13 inch layer the cooked and drained pasta, then the carton of cottage cheese, and sliced cream cheese. Pour the hamburger mixture over the top and sprinkle with the diced green pepper and sliced green onions.
Bake in a preheated 350 degree F(175 degree C) oven for 35 to 40 minutes. Let stand 10 to 15 minutes before serving.