Preheat the oven to 350 degrees. Cook the pasta according the package directions.
Brown and stir the ground beef with the onion and bell pepper until the meat is no longer pink.
Add the tomato sauce and the drained pasta to the meat mixture and stir.
In a medium bowl combine the cottage cheese, cream cheese, sour cream, and green onion.
Spread half of the meat-pasta mixture into the bottom of a 2-quart casserole dish. Cover with the cottage cheese mixture. Then add the remaining meat-pasta mixture and spread to cover evenly. Cover and bake for 30 minutes.
Remove the casserole from the oven and top with the Italian cheese. Return to the oven and bake for an additional 10 minutes uncovered or until cheese is melted. Cool slightly before serving.