Preheat oven to 350°F. Spray baking dish with nonstick cooking spray. Cook ziti according to package directions. Drain, and rinse with cool water. Set aside. Meanwhile, crumble meat in a large skillet coated with nonstick cooking spray. Add onions. Sauté until meat is fully cooked. Add spaghetti sauce. In large bowl, combine cottage cheese, Parmesan cheese, egg, parsley, and garlic powder. Mix thoroughly. Add cooked ziti and mix well. Spread about 1/3 of the meat, onion, and spaghetti sauce mixture in bottom of prepared pan. Spoon ziti and cheese mixture into pan. Pour the remaining sauce mixture into pan. Cover with aluminum foil and bake for about 30 minutes.