Preheat oven to 350 degrees. Lightly coat a 2 quart baking dish with cooking spray. In a large skillet cook the ground beef and onion until meat is brown and onion is tender, drain. Stir in sauce, salt, garlic powder, and pepper. Remove from heat.
Cook macaroni. in a medium bowl stir together cottage cheese, cream cheese, sour cream, green onions, and pepper until combined.
Spread half of the macaroni in the baking dish. Top with half of the meat mixture, then all of the cottage cheese mixture, spread evenly. Top with remaining macaroni and remaining meat mixture. Sprinkle evenly with Parmesan cheese.
Bake uncovered 30 minutes or until heated throughout.